[Austin W Hogan]

Aaron: I read Don's post after I replied. I checked three more guns; a D lifter, a D hammer, and an A lifter. All of these had the 4 pin lock mechanism used on D grade and higher exposed hammer guns. All three had minimal side to side movement in the rebound notch.
I think the answer is that if your gun is a D,C,B, or A some lock work is in order; if it is a T,P, or G the lock is probably alright if it firmly engages the rebound and cocking notches.
I still learn something every day.

Best, Austin