Harmy said:

I'm pretty sure, that the pieces of film added to the negative in 1997 should be recognizable not only by their content but also by their markings, so should they want to really do a proper OOT restoration using the negative, it shouldn't be a problem to identify exactly which shots have been changed.

You're assuming competence and dedication on so many levels here...

Cataloguing all of the original elements properly I believe in. I've got some doubts concerning storing them properly afterwards. Giving enough of a crap to keep them that way for 20 years I just cannot see happening.

Call me a pessimist, but I've seen and read horror stories about film restoration. The original film elements are never in good shape, even if they were supposed to be handled well. It would be a pleasant surprise to learn that someone did indeed take care of them.