Quoted from noopy:I have a Bally supersonic that is missing whatever part locks the back box and holds the backglass in. It does have a lock and key but the lock doesn’t attach to anything. I can’t seem to find that part online anywhere, what am I missing?
You're probably looking for the lock assembly. Someone took pics in a WTB ad here:
https://pinside.com/pinball/forum/topic/bally-back-box-lock-assembly
I don't think anyone has reproduced the long rod, so you'll need to find someone parting a machine from that era (1979ish Bally) out.