Nice pictures but the glare makes it difficult to read numbers. If it is 3445 0 this would fall in a variation between 5196 f and 8810 q,one of about 90,000 pistols made in 1943-(each letter supposedly accounts for 10,000 pistols) An earlier byf variation accounted for about 52,000. A late byf variation 43 accounted for 5000.
Your variation is part of 7.0% of total P.38 production. (all manufacturers) Obviously 1 of 90,000 does not suggest rarity. These numbers come from Krutzek's book published in 2018.
All of these variations should have , on the left front of the slide "P.38" followed by "byf over 43". These are bold letters. I cannot make those symbols out perhaps because of the glare or whatever. The numbers I can read suggest matching numbers, but if the symbols mentioned above do not exist, it suggests someone has ground them off for whatever reason, re-blue etc. If this is the case the value is greatly reduced, but this may be a photographic problem..
Personally, I believe the Mauser-made P.38s (byf) have better machine work than Walthers (ac) starting in 1943, and certainly Spreewerk. Mauser seems to have kept their standards high right to the end of the war (and beyond) .
