Have you actually changed something in those files? If you just open them without any editing, then these functions are greyed out, because there's nothing to undo or redo. However, by the way, if you close one of these files (without having done any editing) you will still get a screen asking you if you want to "Save Changes." Just say "No" That's been an annoying Finale feature for a long time.

However, by the way, if you close one of these files (without having done any editing) you will still get a screen asking you if you want to "Save Changes." Just say "No" That's been an annoying Finale feature for a long time.

Absolutely drives me crazy every time. I've got to finally just file a bug report on this. It's annoying and can create confusion.

If you open a Finale 2012 file in Finale 27.x, it will surely ask if you want to update the format. Although I would not let it update the articulations, I would certainly save the fine in its updated format under a different name. That should at least give you  access to the new features you just paid for.