the pictures are not the best, but in my opinion looks the dagger like an original non marked WKC in very poor condition.
A very rough WKC missing blade release mechanism and push button as well as the bottom scabbard band. The materials look to be all brass so not the latest produced navy dagger.
Maybe about 200€ for somebody who will use it as a letter opener? I don't know. It's not easy to say it for sure.