Anyone know where to locate the model # on one of these? It's a 1994
vitage unit installed in a one piece shower stall and is behind a
mounting plate. The unit got really slow on hot water output and is
now starting to make a squealing sound, so I'm thinking maybe there's
a seal that needs replacing. But without a model # I don't know which
parts to get. Does my diagnosis sound correct?

Thanks so much for your input!