In the bad old days of open reel tape, (OK, I confess, I still have an open reel tape drive on one of my Suns) IBM, besides the fact they used EBCDIC, (which the dd command translates just fine) also had two tape formats unlabled, which could only read one file, then read the next, down the tape, and labeled which contained tape headers explaining what machine density and OS made the tape, and aslo file headers so you could name files and skip files at higher speeds. On my Sun in open reel, I see the labels as small files, since the Sun does not DO labling, it treats every tape as an unlabeled tape.
Best solution: find out if they will accept an unlabled tape, second best, get them to send you a labeled tape and save the labels on your Sun as files and always write those files back then put your data on. (ideally you would edit them with real specs) I tried to remain child-like, all I acheived was childish.