Caveat emptor, so it would seem, especially when it comes to eBay.

I really have enjoyed playing Hot Hand when given the chance. Hope you can get this one running nicely - it sounds like you know your way around a pinball machine.

Now, in answer to your post I believe the area you are referring to above the flippers are the slingshots (aka kickers). It sounds like you are after a plunger for the coil.

You can probably buy knockers and coil shafts from our sponsors (pinballspareparts.com.au and rtbb.com.au). There is a manual available for download at IPDB (ipdb.org) which should help you out with part numbers.