Backup history from client of the tape copy and include the aged data option in advanced. Right click on the job and choose to view media. Greyed out would be aged. You may have tapes where not all the jobs are aged, they can't be reused until all jobs are aged as when it is first mounted to be written to the OML is overwritten so all pointers to existing data are removed.
So if I view the jobs of a client and it shows no greyed out jobs does that mean there are no tapes out there that have expired jobs on them for this client, that have not yet been fully aged out?
Our hope was that there might be an older job for a client that is aged out but still on a tape and we could reindex it and get the data.