You guys also seem to be forgetting that the OOT has already been somewhat restored as far back as the '97 SE. Proof that the original versions exist intact is right in the 2004 box set. Watch "Empire Of Dreams". When they get to the point where they're talking about opening day and it cuts back and forth between clips from the film and everyone reminiscing about the day, all those clips are from the pre-SE version. The proof of it is the opening crawl - it doesn't say "Episode IV A NEW HOPE" on it.

Lucas keeps EVERYTHING on file somewhere, somehow. He's not gonna destroy the pre-SE versions of the film. He knows that as soon as he does a decent release of the OOT that sales on the SE's will drop off the map. He's probably got the OOT stored away with instructions in his will not to release them until the moment of his death, because he knows that that will be the point that he won't be able to stop someone else from releasing them against his wishes.