SA Marine daggers (SA Kraftbooteinheiten) have brown handles, black scabbard and gilt fittings. It's mentioned in a period book. Just saw it recently.
Therefore if the fittings are silver, it's most likely a NSKK dagger with an erroneously black painted grip. Presumably due to a misunderstanding of the order - instead of painting the scabbard only, the entire dagger (scabbard and grip) was painted black.
