Well, the Walther Sportmodell was extremely popular, both with the SA and the general public. So much so, that during the development of the KKW, BSW basically stole--I mean barrowed--the Sportmodell's bolt design because BSW couldn't seem to design any trainer that anyone liked themselves. BSW even incorporated the Sportmodell bolt into their short lived Meisterschaftsbuchse rifles.
I guess it would make sense for Walther to keep producing them throughout the war, as popular as they were. If it has the Eagle/N it was made after 1940 (I'm drawing a blank, I think thats the year they switched from the BUG proofs) after all it wasn't until the Sportpalast speech around mid-February 1943 that the Third Reich mobilized the general public for "total war". Before that, the Reich wanted the general public to have the same standards of living as before the war. Your into commercials.. when did they stop producing those? Just speculation on my part, but it could POSSIBLY be a factory pickup, the Americans were advancing so quickly in the last months of the war that Walther was literally moving their K43 production machinery and workers a few miles east every couple days. I wouldn't think they'd take Sportmodells with them at that point in the war. Thus, plenty of booty for the taking. If not a factory pickup, it wasn't far from the factory because the Allies, controlling the airspace, destroyed most of Germany's supply chain network--rail. Why move .22s around when you can't resupply troops at the front with more effective weapons? Again, speculation on my part.
I believe Walther and JGA were located close to each other. This why I think the above makes sense: The last serial record for a JGA DSM34, SN 8874, as listed in Simpson's book, has a Eagle/N firing proof, but no logo. He states GI's could have put them together at the factory. I have a JGA DSM34, SN: 8734 that I got from an estate in NC, I've seen 8726 and 8739 (ironically 8738 is listed in Simpson's book, consecutive numbers!) all three rifles were located in Western NC... all in excellent condition. Someone brought them back, maybe a higher up? What are the chances that those rifles show up in NC, all located less than 60 miles apart, 85 years later and 4500 miles from where they were made in and only 13 serials apart....
Glad to see your finally leaving the dark side Clay. Welcome to collecting trainers, it's addicting as hell and not costing $3000+ per rifle (unless your shopping at Simpson's website) you can quickly start building a decent collection with so many variations. Super enjoyable to collect because you can actually shoot them, they are super accurate, draw the crowds at the range and no bad bores because .22 ammo wasn't corrosive then.