Hope that answers that; but just for fun, lets pretend it is. Now if we happened to find the stargate on October 28th, 1994, the day the movie premiered, that'd be weird, as, how could we make a "cover" for something that's not happened yet.
Just the theory going forward is that Stargate, the movie and TV shows, are a "cover", much as 'wormhole extreme' was within the show. As such, the stargate would need to have been found before 1994, and likely, before 1993 also.
The movie was likely created when someone in the know approached Dean Devlin and asked him to craft a cover story, and that he involved Emerich, and any "backstory" to this was concocted. Given the role the air force plays (something that no other sci-fi show does, usually referring to space travel folks as some sort of navy) it's likely the air force has the actual stargate in our little fictional examination.
It'd be most likely that only the basics were handed over. "We have a stargate that we found in ancient Egypt that allows us to travel to other planets. We are not sure who built it, but we've met aliens, and not all of them are friendly. There are humans living on other planets." As such, it is my guess that ideas like the goa'uld are fiction. It is my guess that certain real events did make it into the show, but that a good 90% of the episodes and plots are pure fiction, and that even the real events that made it into the show were twisted to fit the show itself.
Some plot points / ideas that came from this fictional reality we are looking at, are as follows:
Atlantis was not across the ocean, it was through the stargate.
The government tried to shut down the stargate, but this was stopped when earth was nearly invaded.
There are a race of beings who are willing to help us.
Arriving on a planet sparked off a war on that planet.
Someone stepped through the gate prior to it's official "activation" (torment of tantalus)
Looking at a possible government shut down, the time that makes the most sense is 1989. John Tower was nominated by the new President Bush (sr) as the Defence Secretary.
Right at about this same time, the USSR was making steps to end the cold war (accepting the rulings of the world court) and the USA was carrying out nuclear tests. In the month prior, 6 rockets launched into space, and on the 13th, the space shuttle did as well. This happened just hours after a massive "solar flare" knocked out power for Quebec, and showered north america with 'solar particles' which cause auroras as far south as florida and texas.
Importantly, as the day approached, Tower, a former Senator (and therefore called "Senator Tower") was rejected by the Senate. Was this because Tower was the Kinsey of reality? Tower wanted to shut down the program? Tower was killed in an airplane crash a few years later.
Donald Ratsch even recorded space shuttle communication, saying an alien spacecraft was under observation. Of course he later claimed this was a "hoax", perhaps under great pressure?
One question may be where is the stargate. My answer to that is Area 51, which I note, is an air force installation. My guess is the decision to put it in Colorado was that of the writers and producers, and not something instructed by the Military. If anything, the Military may have told them outright to not put it in Area 51.
So that covers the where, but when? As eluded to earlier, finding it in 1993 makes little sense; so when was it found and activated?
I believe, in this fiction, that it was found among the relics of "ancient egypt" by the British, and that the British managed to activate it, briefly, and someone went through it. It's possible this happened when it was first found, and hence, why it was never publicly disclosed. The British, though, were unable to figure out exactly what it is, does, or how to work it, but did know that it would be a bad thing for Hitler to get. As such, I suspect it was sent to America, with the deal that the UK would be kept in the loop.
I believe that the Stargate was first activated in 1968. Possibly a year earlier or later, but right around this time, possibly a few years earlier even. Consider that the Internet was officially invented in 1969, and that right after this period an explosion in transistor technology allowed for what became modern computers.
Johnson was not popular with the 'establishment' of the government, and so, likely, was not told, as the new President would take office soon. This means Nixon was the first President to be aware of the stargate. In the UK Harold Wilson was Prime Minister, but there were suspicions of him being a soviet stooge, and so he was not told. I also suspect that Heath was not told, as, at the time, his governor was tenuous, and Wilson could return. When wilson finally resigned in 1976, they finally told his successor, James Callaghan, who is known for being a bridge builder with the US.
When the Soviets found out is open for debate. If the gate was first activated a bit earlier, it's possible that things like the 1967 outer space treaty was a result of the stargate; with the Soviets wanting to limit what the US could do. However, I am certain that Brezhnev knew sometime before his death in 1982.
I don't believe that further worldwide information came out until 1975-1984 or about that time. Leaders like Helmut Kohl, Francois Mitterrand, and Brian Mulroney were likely informed. It's also logical that the leaders of Japan, China, and Italy were also informed. In fact the G7 may have simply been a front for the leaders of the countries aware of the stargate (except the two communist countries mentioned) to meet. Consider that Canada did not join the G7 (which was the G6 in 1975) until 1976. There were suspicions among some that Pierre Trudeau was some kind of Communist, and so, holding off on telling him may have been the result of this delay. Consider as well that Italy was also seen as a lesser partner within the G7, and as a country that switched leaders often, this could well be the reason.
Today, I fictionally believe the governments of the G20 all officially know about this stargate program. I'd say that most other EU countries also officially know, such as Spain, the Netherlands, and Belgium, as well as countries too small for the G20 like Ireland, New Zealand, and Switzerland. Outside the G20/EU/NATO, there is another group of countries that potentially know, and that is former Soviet republics. Outside of that, there is just Israel.
I do, however, think that some countries "unofficially" know; that is, they are aware of the stargate, but the US will not confirm it's existence to them. Iran is a clear member of this group, while Pakistan is a very likely member; having stolen that information from India.
So what is the gate used for? Mostly science I'd say. I doubt it causes nearly as much problems as it does in TV Land, and is likely far more dangerous to use. IE folks on our side die after going through the gate, but the threat to the planet is very low.
The idea that we bring back some kind of alien computer and within a week can advance our computer information by decades is insane. What happens is that they find some kind of alien computer, look it over, and figure out that somehow, using only transistors, they've managed to cram an entire processor into this puny little area. So; they get that information out to science, and let them figure out exactly how that's achieved. IE the main benefit is that science is pointed in the right direction. They are basically told "here is something that will work; find out how" and that is why some developments happen so fast.
I'm also fairly certain the Stargate was moved out of Area 51 in or around 1995. Where to, however, I can't say for sure. However, ironically, Cheyenne mountain saw substantial "upgrades" at around this time, but given that people have pestered around (so much so that they had to put up a fake sign saying stargate command on a mop closet) it's likely that if it was moved here, it was again moved. A good location for this would have been Kyrgyzstan as a bone thrown to the Russians, but after the events in Ukraine, it is very likely it has again been moved.
And thus, the stargate is revealed. Or at least, if we pretend it has been, we can finally end this post which is starting to get rambly and has gone one for too long.