Do you forget this one Ger?
Minty NSKK RZM Dienstdolch by Wusthof M7/19 with hanger
This maker Mark also deviates off from the strict RZM makers mark rules but it is ok. I believe that we still have a long way to learn everything about the daggers of that period.
And if we look to the daggers made by J.A Henckels (M7/10 we see the same different M as Christianswerk (M7/1).