I found a better photo of the name plate, not sure if it useful.
Sure is, thanks :-)
Obviously, it's an original plate and at first glance it seems the airtanks wasn't tested since 1943, which could mean it was not used postwar.
Certainly two details differ it from an "ordinary" type 1215, so I'm still a butt puzzled: Might be a variant (there's basically no information/details available on the german exersiceheads), or it was in fact in use post war. Despite the original shield, I'm leaning towards the latter:
* The colour is certaily post war (and complies to Bundesmarine standard).
* The details on the tracking-lamp cover and the nose ring indicates postwar modifications.
* Testing of the airtanks might have been tracked by use of a register, in stead of stamping it into the shield (we did that in RNoN-service)
* The stock of exerciseheads were low after the war, and always in high demand (in Norway several new heads had to be manufactured after the war, and that was also the case in West germany). Unless the head was faulty, I'm sure it would have been used post war.