What is the first year the HP 500 would have been available as a factory install from Fountain.
Thanks

Probably 1994 or 1995.

+1

The owner says it is a 95. I notice my 97 HP500 has mirrored valve covers. Does this look like a genuine HP500?

Yes. Early 500's had the finned valve covers and Gil-Mercury exhaust. Those are the ones that had valvespring problems.

Yep, the newer valve covers came out a few years later. All the carb HP500's had valve spring issues.
The early years also had reversion issues. They switched to a different riser after a few years as well.