It looks like brass type alloy and both prongs were cut short.
We have many examples of Assman badges here. Do have a look at them.
For me looks O.K But always if someone showing me skull covered in cocon of sand Im little suspicious (:
At first heft to be washed in destilated water and leter we can see what we have
Here some Assmans for compare (:
One wrong stamped also orginal (:
P.S One skull on blue surface and one the red surface are the same skull
All the skulls shown are authentic pieces.
Especially from that last picture , this indeed seems to be the CUPAL version of Assmann .
These are extremely rare , where the zinc versions are quite common .
Only a handful known - congrats
Wow! Good to know! :-)