The location of the piston looks normal. The bid divot in the middle of the piston does not. I would proceed carefully, forewarned that someone has beat on the piston to free it up. If you can free it up, though, and you can find an impeller and head gasket, and everything else looks good, it’s probably worth the effort. These are pretty good motors. I ran one for a few years with my boys and sold it to someone who was still using it last I knew.
Tom