I would just run over to the nearest wrecking yard to get one. At most, you could pull the stamped plate off and sand down the contacts a bit on the copper lugs. They even sell replacement lugs for cheap if needed. There's nothing to these little starters.
Once a local rebuilder was mentioned I remembered we used to open starters up and scrape the commutator to get them going again.
This one will make about a half turn every now and again, then go back to just giving one CLICK. I get the same behavior with it off the car. I may pull that stamped plate off to see if there's anything obviously ugly inside there. The rubber protector over the external wire that connects the solenoid to the starter motor was worn out and torn up though so if I were able to get it going again it would need that replaced before I could bolt it on the engine.
FWIW it looks like a Powermaster 9513, although I don't remember noticing that it had an adjustable mount. It's an older one before they swapped the connectors around.
