What exactly does it mean for the negative to be disassembled?
The negative has been conformed to the SE since 1997. George decided to cut the changes directly into the negative because, as far as he was concerned, the SE was the official version of the movie now.
We recently got confirmation from the relevant person at Fox that the pieces of the negative replaced for the SE were indeed put into storage and not discarded.
I think I remember reading on zombie’s website that the negative need not be disassembled to reconstruct the unaltered version. Because a modern restoration would be done digitally anyway, they would simply need to take a scan of the o-neg as it is now, scan in the pieces that got replaced, and rebuild everything in the digital realm.
For further context, the negative is the first-generation source for the footage used in the final cut. They are also without any color timing as that comes later in the process, and unlike a 35mm print, which is a few generations down from the negative, there is only one layer of grain to deal with (this is not the case with SW as there is optical compositing).*
*if I’ve made any mistakes, please correct me.