There is current work in STEP AP242 to annotate parts of a design with UUIDs to make it easier to work out if elements of a saved file are new or modifications of a pre-existing one.
UUIDs don't tell you that because when does changing a part make it a new part and thus a new UUID? Unless the users is naming all parts - but that isn't what UUIDs normally are and opens a different set of problems.
The problem is hard. I wish those working on it luck, but I don't have high confidence that it is solvable.
