Bob, I think you'll have to get out the glue and make repairs to the boxes because most places that used to have RtoR tape have long ago thrown it all away.
Mitch has had to do that with his boxes - he says the glue used by librarians to mend books, is the stuff you want. And don't use tape.
But you might also find the leader tape also needs to be respliced onto your tapes but magic tape should do the job and last for another 20 years or so.
Cheers,
Robyn