I mentioned this elsewhere, but e/29 is associated sometimes with e/14, and both were some of the earliest waffenamts for Berlin area firms, - specifically RSS on early interwar G98's, some S28's I believe also, but mostly I think it DWM related after the war, possibly like with WMO making the parts to upgrade the RS's.
Ken use to have a DWM/18 with e/29 TG-FP and e/14 RS parts, these were forerunners of the S28 project, - old DWM/18's and late Oberspree's, which are directly linked to the latter S28's.
Secondly, e/29 is also associated with Pössneck (Thüringen), south of Jena and Weimar. Typically on holsters 1937-1941.