Nice rig - i also respond at the P.38 forum...
The brown holster, you know it was used by either the Gendarmerie (rural police), motorissierte Gendarmerie (motorized rural police/highway partrol) or the Verkehrspolizei (traffic police). I don't know if your pistol was found in Norway or somewhere else, as this would indicate one group or the other might have used it with the brown holster. And, you know the gun in brown holster was used only by an officer or Kriegsoffizier (senior non-coms given temporary officer rank during the war) of the Gendarmerie, or any member of the other two units, as an order of June 1940 restricted 7.65mm pistols to only those ranks.