Here is my Nazi era Walther PPK It was made around November 1939
The crown N stamp was only used until 1939, 1940 and after it was an Eagle N, the PPK was released in 1931 as a pistol for plain clothed or concealed carry work whether that be police or military ,
All pre 1945 made guns should have Zella Mehlis engraved on the slide, if its Ulm/Do its postwar manufacture.