This ebay buy it now arrived today. I'm pleased to say better than expected.
The seller described it as "no markings", except the scratches on the back of a previous owner. I can't decide what "they" were trying to inscribe, a name- then #13 frame? - then
#2824 Ret., puzzling.
I was hoping for a date, and sure enough, in a little bit unusual place is the marking for Hermann Floehr, 1916, Coeln.
This identical mark is to be found in the green edition of Goertz and Sturgess on page 1351(volume III). For the red edition you can probably find the same picture in the chapter on "Military Holsters/Stocks".
Also received with an original cleaning rod, but not marked. No tool left in the pouch.
Holster stitching and leather in super condition save the closure strap which is pretty fragile and worn.