We’ve gone over this before but just to be clear the SINOXID priming was developed from 1926 and Patent applied for by Dynamit Nobel at Stadeln Work (RWS) in Germany on 01 Dec 1928.
SINTOX® was according to Dynamit Nobel AG , the first environment-friendly priming composition launched on the market. Sintox was a protected trade-mark from c1980.
The R in shield was the standard RWS hs for RF cartridges from c1905 and is not SINOXID primed. I believe that the D (for Durlach) was the standard RF hs for Genschow.
Evidently On 1 Jan 1928, a contract between RWS and Gustav Genschow & Co (Geco) came into effect. The content of this agreement was as follows: The pistol cartridges and shotshells of both companies would be manufactured in the Durlach plant of Genschow and the Rimfire, revolver, Flobert-cartridges, primers, cases and air gun pellets of both would be manufactured in the RWS plants in Nuremberg and Stadeln.