Topper in good shape or missing?
Is the board in good shape with no hacks or battery leakage?
If the only problem is a worn playfield, they make repros. Pinbot would be a good project pin imo, not a whole lot going on with it. You can do a pf swap and rebuild every mech and learn a lot as you go.
Like stated above try to get it for less than 800, but when they reject that offer... go with your gut or wait for another one to come along there are a lot of Pin*Bots out there.
Good luck!