In connection with other research I am doing, I have spent a bit of time re-reading Albert Speer's old book, Infiltration, How Heinrich Himmler Schemed to build an SS Industrial Empire. According to Speer, Himmler's minions were steadily finding ways to make themselves invaluable to armaments production (beginning in the Spring of 1942). Basically Germany's leadership came to the conclusion that forced laborers were going to be needed to make weapons for Germany. Below is an example of how the Gustlof Work was employed on another documented program for carbine production. It is not too far of a stretch to suggest that perhaps Gustlof technicians and equipment may have been utilized at the Spreewerk too.
“Two “tests” were to be made in the manufacture of carbines: in Buchenwald and in Neunengamme. Schieber* had announced that monthly production of 15,000 carbines should be launched at Buchenwald within three, or at most, four months. This was not an exaggerated goal, just a simple test case; the production” (as in assembly) “of carbines requires little manufacturing expertise. In any case, the machines and expertise were to be supplied by the Gustlof Works.”
Page 18, “Infiltration, How Heinrich Himmler Schemed to build an SS Industrial Empire” Albert Speer,
* Schieber was on Albert Speer's staff, but was also secretly an SS officer on Himmler's staff.
As previously noted, the Gustlof Works waffenamt inspector was assigned Wa18.
The above information is my opinion. Before this idea takes on the mantle of an historically accurate observation, we need to find at least two more examples of locking blocks with waffenamt 18 on them. I think this information and way of looking at the possible involvement of arms producers other than Walther early in Spreewerk production has legs, but needs much more input from other owners of these early P.38's. Please feel free to pester any and all owners of these early guns to check the locking blocks for this unusual stamp.
My gracious thanks to Mark, Steve, Ron and my fellow P.38 collectors out there. Without freely sharing information, I'd be "just another Bozo ridin' the bus to Crazy Town!"
I'm having more fun than I dreamed possible with this hobby. There is indeed always one more P.38 to buy, and one more mystery to discover! Good hunting to you all!