Most of these were confiscated from dead or captures soldiers and thrown in a pile with the magazines removed and thrown in another pile.
One might surmise that later production like 1944 would have been captured closer to home and by a western power if it has no Russian marks. We know that Mauser's records were destroyed but not sure what was left intact at Walther since Zella-Mehlis was in what became East Germany.
Check the P38 Forum for a better chance to find an answer. Some of those folks are here too so.....
You'll be able to easily enough find the month that your pistol was made, and the factory that built it, but the soldier who carried it or where that soldier went? That won't happen. Keep in mind that the Germans were producing more than 100,000 P.38s a year at each of the three plants in 1944: Walther produced 130k, the Mauser plant turned out 145k, and the Spreewerk plant churned out 127k pistols. That's a lot of P.38s.
What are the specific marks on your pistol? How about some photos?