It is what is called a "Waffenamt", or "Weapons Office", stamp. It signified that the weapon (or part) passed German Army inspection. Each inspector, or office, had a different number, and they moved around some, so the same model can have different numbers at different times. It's a whole field of study for German WWII gun collectors.
The Radom is a very well thought-of gun. There is at least one big book about them, and a couple of small ones. Gun Digest also did a big article about them, in the early 1990's I think.
Everything looks original, except for the number on the floorplate of the magazine. Common 3-lever variation without the stock slot. Original Radom mags were not serialized. A numbered mag might signify post-war police use...
If the gun is not import marked and the grip straps are not worn(most are), then I would guess about $750-850 for the rig
The holster was made at Steyr, where Radom pistols were assembled. For security reasons, the Germans did not allow barrels to be made at Radom, so the gun "kits" were taken to Steyr (in the former Austria, after 1938 part of Germany) where barrels were made and the pistols completed and assembled.
The holster marking is "P. 35 (p)" or Pistole 1935 (Polnisch), the German designation for the Radom. (The BHP was P.35 (b))