Originally Posted by
10x25mm
You have a middle period, pre-war commercial Walther PP. It has all the improvements made in the first three years of production and none of the economies which were adopted from 1940 on. It was most likely sold to an individual within Germany, but could have been carried as a private 'honor pistol' by a high ranking police, military, or SS official. The only export pistols from that era which were not proofed by the recipient country were those which went to Switzerland and the U.S., but these were few in number. The Swiss recognized German proofs, but no one else in Europe did.
These pre-war PP pistols usually have the last digits of the frame scribed inside the slide in the vicinity of the ejection port, but not always. A matching slide usually raises the value by about $ 100. A mismatched slide is a detriment. A correct magazine (polished body and base plate) will cost you around $ 150, but it will function with post-war magazines without any problems. Pre-war magazines are still offered from time to time on GunBroker.
These pistols, without magazines, usually sell for around $ 400. Most are in far worse condition than yours, so yours might be worth $ 500 without a magazine.