The Walther PPK and PP Model pistols used by Police and Military were largely NOT individual purchase, I believe. Many of these pistols are knonw with military and police proof marks. The ones used by para-miitary organizations were often private purchase by individuals and in some cases, by the organizations themselves. For the most part, the ammunition used with them, even by the military, was commercially marked and commercially packaged. Even the steel-cased Geco cartridges are from commercial-style boxes and with standard commercial headstamps. FN, run under the stewardship of DWM, was an exception, in that they made dated military and police cartridges for the German authorities regularly during the war, often in steel cases, both with FN headstamp and DWM headstamp.
The true military boxes are much scarcer than the cartridges, and material in .32 caliber (7.65m/m Bronwing) is much more common than .380 (9mm Kurz) which for some reason, the Germans were not in love with. That is evidenced not only by the considerably fewer caliber 9mm Kurz Walther and other small pistols made during that era, compared to 7.65mm, but also by the German's mandate of conversion of production of pistols like the CZ 24/27 series and the Hungarian Femaru, along with the Browning M1922, to 7.65 Browning from 9mm Kurz. Even after they became officially occupiers of Northern Italy, the 9mm Corto caliber Beretta production all but ceased in favor of 7.65mm.
There were some dated headstamps for police, and at least two military 7.65mm headstamps during WWII, "aux" code and "dou." code. The latter is rarer than the former in 7.65mm, although the dou. code also appears on steel-cased 9mm Kurz (the "dou." 7.65 is in a brass case) and they are fairly common even today. There were also Geco cartridges with "X" headstamp for use mainly in the Czech P27 mit schalldampfer (the silenced version of that pistol).
There were also a couple of military headstamps in WWI, and military style boxes from at least two makers, one of which was "DWM" using the "DM" intiials on the box, as they cntinued to do so, for whatever reason, on military boxes and some headstamps thru WWI, even though they had gone to DWM commercially years before that war.
If there is interest, I could scan the very few German military boxes I have in these calibers, along with the pure military headstamps. To scan the commercial boxes would not prove much, since they are common and they are in large enough number that it would be a rather daunting task. The same for the headstamps.
Bear in mind, that basically any headstamp in these calibers from all of the countries that made that ammo - Germany, France, Poland, Belgium, Yugoslavia, Italy, Hungary, Czechoslovakia, etc. could undoubtedly be found in pistols carried by German military, especially during WWII. The same goes for the pistols themsleves.