msycamore said:

IIRC, Robert A. Harris mentioned years ago that the actual original cut negative wasn't altered (it was disassembled, cleaned up and reassembled). A new duplicate negative was what all the work was done on preparing Star Wars for the Special Edition. Everything else is just horror stories made up to conveniently make it seem like a restoration is somehow impossible.

I really hope that's true. And it does make a certain amount of sense, because otherwise you'd be waiting for every single new shot to come through the pipeline before you could even start putting the movie back together.