Quoted from catboxer:
Sharpshooter did not have a knocker, correct?
Correct. From my research, GP's use of the knocker is very curious given it's importance in pinball. All their cocktail machines had knockers except for their last one, Lady Sharpshooter, where the schematics list the knocker as "optional". Yet, uprights didn't have knockers until at least after Global Warfare and perhaps as late as Andromeda. Exactly when, what, and why I do not know and any answers I have would be speculation. Cost savings would be the guess but seems a penny-wise, pound-foolish move compared to the competition.