Is there a workaround for this issue, without generating a nightmare of extra work?

I’ve got a travel guidebook I ‘inherited’ that we’re going to update for 2019, it wasn’t in book form yet, just 17 individual .indd files with associated folders for linked images. In a hurry to make it a book file and clean up, so we could export 2018 ebooks, none of the file names were changed at that time due to a lot of image links that we didn’t want to break. All of the original document/chapter names are variations of 2018 or some other name. Now that we’ve had time to catch our breath and regroup for 2019, I’d like to change the .indd names for future use and relink to the book, but I’m afraid all of the Index links that have been added since making it a .indb, will be lost too.