Hi Kirstin,
The Wappen looks fine and original to me, I don't see any signs of resoldering.
The slits for the Wappen remain a mystery to me, as well as the unusual "cracking" of the black lacquer, and the unusual location for the unit marking.
My advice is to take your time and find out what exactly you have before you make any changes; wouldn't be the first time that a helmet doesn't seem to conform with the regulations and parts were changed out, only to find out later that it was all original after all.
Regards,
Lars