I think you are in the right neighborhood on value. I think for that price it’s worth it to at least go see it and fine tune your price (lower) if necessary.

Star Pool was my first pinball machine. When I bought it, I didn’t even know enough about pinball machines to know what I did and didn’t like. I think I also paid around $400 and played the heck out of it. Machines from that era are great introductions to the EM hobby since they are plentiful and do not require a big up front investment. If you enjoyed the game, then I say go for it.