Gulp, yes. Oh I know it is a HUGE pain in the behind to do on Genomemate but you won't have the correlation unless you create a secondary Spreadsheet to show the old and then the new ID's, as a quick reference.
Just better in the long run to do it again - then fewer chances to have a mix-up.
This is something I am looking at today - How is everyone else handling this - Just downloading all your matches and updating all your spread sheets/uploading to your programs?
Mags