The holster is definitely a 1950s German police holster from the state of Nordrhein-Westfalen (NRW), specifically for the FN High Power, which was standard issue from 1952 to 1966. Many nice HPs on the US market from that period are ex-NRW pistols, which were not otherwise marked, unlike the Austrian-issued ones from the same period.
The NRW holsters were made by at least three different manufacturers and are not to particularly tight specs. Geco and AKAH are only the best-known.
The holster in use. There were standard black as well as white versions for the traffic police:
