That Galaxy amp looks exactly like the Palomar version, except for the name printed on it.. Makes me think there's a pretty good chance the guts are the same too, but without seeing the inside it's impossible to know for sure.
If you go back to the ebay ad you can see interior pics of the unit...not Hi-res but they are ok..
I found a Texas star in mint condition for $200 from a trustworthy tech in Ca., and should have it next week...I think I will be happier with that unit anyway.
I couldn't find TS 500's under $320 new...the used ones were n Craigslist with unknown sellers.