Frank, As far as I know (as someone who is not a mechanic (and who TRIES to not impersonate one on the Internet)) is that a C-75 or C-85 is a C-75 or C-85 whatever plane it's mounted in.
Ask them if they have someone who does more old airplane work. However, swapping out the alternator may only be a 30 minute job (plus the paperwork) if they have a matching one on the shelf. Good luck. Ed
