Jim,

Is where the "49" is stamped on the left side upper forward grip frame a common location for original factory stamps for some variants? I do not see this area used for stamps on any of my M1917 examples that I own. Also, a 2nd Model .455 (a non-factory conversion to .45acp) that I used to own was not stamped in that area.

Nor is this area used for stamps on my commercial frame M1917, Brazilian M1917, 25-2, nor my pair of 28-2 examples. That's why it caught my attention right away.

Would it have been applied by or for an assembler/inspector when it was sent back for rework?

(Yes like an idiot with nothing better to do I just double checked all my N-frames.....but once again that's why the "49" on the OP's example caught my attention rather quickly.)