Rick,
I wrote "stamped" without really thinking about it or even knowing. I sold all three of them after about six months, as collectors items, a long time ago, and wasn't paying attention to how they were marked. You are probably right about them being engraved.
I bought the first one, and after having trouble with it, bought two more at the same time, so determined was I to have a good working example, and not believing they could all be so bad. I took the first one to a gunsmith to have a safety lever problem worked on, but then it still refused to feed reliably.
Factory WallMart white box, and then some hotter loads. No improvement. The failure to feed of the other two convinced me to quit trying. Taking out the mainspring and messing with it did not occur to me at that time.
Since the magazines are not available, I did not try other springs there either. All three guns looked new out of the box, could only be 10 or 15 years old at the most, and compared to a ninety year old DWM that was operating just fine, I had no faith in the Stoegers.
Did I give up too soon ?
Anyway, working with a 1917 DWM was alot more satisfying. Rebarreled a P08 4" with a 6" Bohler Stahl Austrian barrel, and it fired just fine without any spring changes. 'Had to adjust the POI quite a bit, extreme banging on the barrel with a 7-foot yellow pine 2x12, and replacing the front sight with a custom made taller sight of the patridge sort, and now it is a tack driver reliably shooting tight groups right on the sights.
This gun had been refinished over a badly pitted and rusted condition, in places, and I stripped it down to white metal, filed down some of the pitted areas, and am letting it re-finish itself slowly now. This photo was before changing the front sight, and changing the grips to wood.