OK, pain in the butt question. I have in my box of pistol parts a bobbed stainless hammer with no half cock. It has "6906 (and some other model numbers) only" laser etched in the side of it.

two questions:

One: Will it work on a 669 that has had a S&W factory frame replacement with a round trigger guard 6909 frame?

Two: IIRC from my days working on department Model 59s in the 80s, a replacement hammer needs some tuning and fitting to the weapon... am I remembering correctly?

Thanks in advance. I really don't need to replace it, as the hammer on it (a black one that matches the black trigger) is fine, and the trigger pull is sweet. I am just curious.