Yeah, one sees that >>teardrop<< crossbolt anchor ever so often, like on this O. Geyger:

https://waffenhandel-zwack.de/bockottoberlin

[Linked Image from thumbs2.imgbox.com]

It looks like a teardrop / white patch on a Canadian Goose.

[Linked Image from thumbs2.imgbox.com]

And the >>F.A.K.<< is most interesting & for the moment all I can muster is the name of Fritz Albert Keßler, but like many initials, that's a longshot w/a limb in the way......


Hochachtungsvoll,

Raimey
rse