Observations on What firms did
First I want to state that just because a Firm did not produce the DSM 36 pattern, does not mean they did not continue to produce or at lease assemble the 34 pattern after Mauser had made the developments and drawing changes.
Clearly some did.
The Suhl Consortium AKA Waffenstadt-Suhl (J.P. Sauer, Haenel, others?) adopted the DSM 36 changes as the example in the attached pic clearly illustrates. Not aware of any competing models by these firms.
Anschutz adopted the changes and as is evidenced the attached example at least assembled them into 1940. This although they had more than one competing model of their own design.
The last GECO's (not sure made by whom or where) adopt the changes as illustrated in the attached example. Had competing designs retailer of all makes at some points.
BSW may not have built the DSM on the new Mauser pattern. I have notes that some of the last high numbers by them were 34 pattern and had Eagle N proofs. One observed SN 192014 which is the high, falls in the BSW KKW range and is the 34 pattern. I have not observed any on the 36 pattern nor have I observed any with Eagle N proofs. Sporters in that serial number range built with BSW markings after the name change to Gustloff, and with Eagle N proofs have been observed. I believe these must have been built on shelved receivers and they trickled out using up the last pieces. They had a competing design and were developing what would become the KKW.
Erma - don't know not observed beyond 34 pattern - had their own competing design
Walther - had competing design, may have continued to produce the 34 pattern (D suffix range) beyond the implementation of those changes by others.
Green Heart - don't know not observed beyond 34 pattern
Paatz - only made a few 34 patterns, scattered through other production, no dedicated serial number range, probably mixed with other guns of various type and caliber,also had competing design
Weihrauch - none observed not likely there are clues they may have contributed to the Green Heart
Bolte and Anschutz - opinion they only made prototype 34 pattern may have been contributor of pieces on Greenheart
Schimdt - opinion they only made prototype 34 pattern may have been contributor of pieces on Greenheart
Haenel - opinion they only made prototype(s) 34 pattern known to be contributor on the Waffenstadt Suhl
Diem - Probably, only made prototype(s) on 34 pattern - further involvement?
Menz - made 34 pattern may have made both patterns or pieces for GECO late after ceasing to market with own logo
Note: Simson was superseded by BSW in 1935 with the NSDAP take over. Some Simson marked receivers were evidently found in inventory and trickle out after that time frame. By the time the Mauser changes were implemented the company was BSW.
To what extent J.P. Sauer was involved remains controversial. Certainly made the receivers, I personally believe they were the assembler on the Waffenstadt Suhl but have no solid evidence yet other than the guns finish, fonts, and other observed manufacturing traits. However, they appear to have been the leading firm in the Suhl Consortium and were clearly the largest production facility involved in the Waffenstadt Suhl. It was one of the more prolific DSM's in quantities produced.
Generally, what I am seeing leads me to believe that most the Deutsches Sportmodells were built the first two years with only a couple other makers besides Mauser continuing past that and some clearly either using up existing parts or producing a few on the old pattern.
This tends to reinforce my previous opinion that the demand for trainers in 1934 and 1935 was certainly one of the first markets for re-armament while the wraps of the Treaty of Versailles were still cloaking production. In 1936 as the 98K and other combat weapons production ramped up and the wraps came off, production of the DSM was no longer a priority. Logical that in those first two years it was a priority.
Contradictions, corrections, observed examples???