[Preventer Wind]

Yes...I must say that is the best theory I have heard. Considering Solid Snake wasn't born until the 70's it makes sense. And this right here taken from an interview with Hideo Kojima:

Gamers .com: You can interpret the reference to the '60s literally, as "the game is set in the '60s," but is that also meant to be a comment on the themes the game's meant to discuss?

Kojima: First of all, I really can't give anything away about the theme of the story -- if I do that, I'll give away a lot of the story, and that's something I obviously can't do. But the theme of the gameplay is the jungle, and in addition to that, it's espionage.

By answering this one part, I'm giving something away, but with Metal Gear Solid, I wanted to create espionage action. Since the previous two games took place in the near future, it's a sort of skewed form of espionage action. Espionage action works best in the Cold War era, so that's where we're bringing the game. That's where the sneaking mission concept works the best, in that era. Instead of having the game set in the 21st century, having it back then, when the United States and Russia were enemies and always trying to get something out of each other, and when you didn't know who were your friends and who were your foes, this is really the best time when you want to do an espionage game.

gamers .com (still a bad word )

So if this takes place during the cold war it certainly takes place before the other Metal Gears.