Dagger with a very smooth blade
 

I got offered this dagger of which I know absolutely nothing. The hilt is made of ivory, the scabbard is of leather with iron mounts and nice decoration at the show side. But the straight blade is absolutely smooth with no markings at all. Total Leng in the scabbard is 32 mm. Does anyone have aun idea how this item could be identified?

My first impression is that it is a recommisioned XVIIth c. main gauche.
Blade could have been erased in the process. Grip not original, pommel no idea.

But as second thought oxidation seems homogeneous.

All in all a left hand dagger, whether or not modified. That guard tells no lies... right ?