Although you already did post before first let me welcome you to the forum!
What you do show us here seems for me to be a legit early KLAAS crossguard variant. A lot of hand enhancement on the wings and the eagle´s chest. Also it looks like there is very nice untouched patination.
Will you please show us the whole dagger?

wotan, gd.c-b#105

"Never look for sqare eggs" as a late owner of an original FHH-dagger used to say.