BSW rear sight base?

I constantly keep an eye out for good parts and saw this come up on eBay today. It's a rear sight base with what appears to be an early e/4 waffenampt, and another marking I have not seen before - circle with a triangle with an S. Has anyone else seen it before? I am wondering what kind of rifle it was on before. Gew98m? Kar98b?

I believe these were armorers rebuild bases made for the 98m. they are proofed for Simson but don't have the additional proof for installation.
I think I've seen this particular base on a 98m, but as always I reserve the right to be absolutely wrong.

The triangle S is an early Simson trademark. The Nazis took Simson over @1937 and it was renamed BSW
So this is probably pre ‘37 made, in the time frame where the e/4 waffenamt was used with the Simson name. Not a long span of time. Paul can be more accurate on details .

BSW took over in September 1933, the change over came quickly with the rise of Hitler and his thugs, -Simson had long been a target due to its military contracts, which there was some typical envy at play from other nearby small firms (some suggestions of French connections didn't help, neither did being Jews but those were incidental prior to 1933 - the charges were corruption and the Simson brothers essentially traded their firm for their lives, escaping to Switzerland, France and then the US - the Loewe's weren't as lucky, but they were heavily capitalized by banks and weren't in a similar position to trade) The letter Bernd helped me acquire were translated for the books Mike and Bruce published.

This is an early RS sleeve, the Simson firm made many ordnance parts and accessories, tools etc (the letter mentions numerous items) This is the earlier logo or trademark, I did some trending on the variation mix, mostly with mg magazines which are dated K-G-36 etc..

N dated S-trademark with e/6
K dated S-trademark with e/6
G-dated S-trademark with e/4
1936 dated BSW e/4

So extrapolated this observation and probably 1935 but could be late 1934