Luger Pin Numbering

[steven c]

I am still a novice with regard to Lugers. This is a very expansive area with multiple changes over the years. My question is to some of you long-term collectors who have had many examples to examine.

These are two firing pins, one from a 1938 S/42 and the other is from a 1939 S/42. The '39 is numbered to the gun. The '38 is not stamped with a number, but appears to be an electric pencil style engraving of a number that looks like 48. Is this an older style type pin that was replaced, or was it just an armorer replacement?

My '39 matches everything down but the clip. The '38 has the same number on the side cover as the rest of the gun, but wasn't fitted to it originally (from another gun?).

On the attached pic, the leftmost pin is the one that's in question. For a '38 and a '39 to be so different, please fill me in. I look forward to acquiring my next Luger. And you guys are right, these are addicting - I've loved them since I was a kid.