Assets were added to all but one book - can we add to FED book now keeping asset numbers aligned?

Summary:

Looking for the most efficient way to add over 4k assets to one tax book (FED) that will allow all books to remain in synch with asset numbering.

Content (please ensure you mask any confidential information):

Most likely due to user error, we have over 4,000 assets that were initially only added to our corporate book last period and it wasn't noticed until last period was closed. We were given the solution to reopen last period for all tax books and run the mass copy process, which worked for all tax books except for our FED book.

Our IT technical resource thinks the solution may be to use an FBDI upload to add to only the FED book, providing the asset number, so all books are now united again (which I assume may be what happened at implementation?) and plans to test early next week when she returns from holiday but we wanted to reach out to the community now to be better prepared for what we might learn since we have held up all asset transactions for the current period, just to be safe.