Never seen it before and not sure it really makes sense? LZA could be abbreviation for Luftzeugamt, it's generally abbreviated this way. Also, Kü marking is seen on Lugers and last I heard those guys thought it might be associated with the Luftwaffe. Of course there is no way to verify if those markings on that gun are real, that I know of.
many thanks
may be luftzeugamt kusten , kusten was a fliegergruppe place , just an idea