Tangs, especially from navy blades (which have to fit into a relatively small, fragile grip - due to the wood core) can and mostly (always?) do show heavliy grinding.
From These few and only showing a certain details pics I cannot see any red flag. Seems to be a WKC or unmarked blade?
Please show the whole dagger or when there is only a blade, at least the whole blade.
Regards,

wotan, gd.c-b#105

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