Look at your 4" 627 Pro - is it's trigger hollow-backed, a la the very first post in the thread? If so, it is a MIM part - not a forged trigger. The hammer is likely the same as the trigger. The 627 Pro is less expensive than a 4" PC627 - which would have both a forged hammer and trigger. As far as I know, all 627 Pros came with MIM parts.

Stainz