vesuvio, imo these daggers always request a careful in hand inspection. A statement only from pics cannot be 100% sure.
But what I can see from the pics, the fittings are those commonly used by VOOS fot their daggers. The etching seems to be in equal quality I have seen on doubtless original VOOS etched blade army daggers. The same for the etched trademark. The fact that the blade is nickled (at least it looks nickled for me but also requests in Hand inspection) also is a good sign. A true ivory grip (same as for nickeling) is also mostly a good sign for the originallity of such a dagger as the (period) grips alone are very rare. Overall, I personally cannot see any red flag but as said, a careful in hand inspection would be needed for any final statement as it is said that there are fairly good reproductions of the VOOS etching lately.
Regards,

wotan, gd.c-b#105

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