Interesting introduction into the hobby, Douggie. I used to own a Hot Hand and it is a well designed and interesting machine. Typical of Early Sterns, the backglass was flaking at the bottom.

The Knocker is typically missing on these machines, and they are hard to source. They usually have a nylon tip that makes contact with a metal strip screwed into the cabinet. I'll look up the part number tonight (if I remember) !