2 numbers on my 1920 Commercial Breechblock?

[HerrKaiser]

Hey everyone, I am new to here and am Looking for some help in identifying my Luger that I bought in January. Based on what I've read in other threads and looked up from Jan Still, I have gathered that I own a 1920 (1923) Commercial in .30 Luger (7.65x21). My question is about a few of the parts, particularly the Breechblock. I know these lugers were made using already manufactured parts leftover from the war, but the breechblock has the matching number (95) on the left side near the joint, but on the back near the firing pin it is also marked "15". Is this a force match, a mistake in original numbering, or what? Ill post a lot of the pictures because it looks like a very nice example overall.