thanks for that.
No, mine is not marked at all apart from Otto Bock Berlin on top of the barrels.
You might remember that we did some research on this gun some years ago without success

date code is 939 and the s/n 366005
we were unable to assign that s/n to any maker for that time period.
If there is any further info since then, I would still be interested to find out the maker.

best regards