OT--sidearms for officers

I have read several times on various forums that in WW2, German officers were required to carry a sidearm wherever they happened to be and that each officer had to acquire it personally at his own expense. Barring very high-ranking officers, whom I presume could carry or not carry whatever they wanted, how did this work? If the officer had to purchase his own pistol, would it not be likely that he would acquire one with commercial and not military markings? Who were in fact issued the millions of P.38s or military Lugers--was it NCO's, medics, artillerymen, etc.? Would officers ever use little-bitty calibers, like some of the American generals did with .32 1903 Colts? What about something even smaller and more token, like a .22 Walther PP? Were there in fact any limitations to the type or brand of the pistol (as long as there was ammo available)? It appears to me that a country who would issue sidearms ranging from Polish Radoms to Norwegian .45s would probably be tolerant about their officers using any reliable sidearm.

Sorry for the bandwith, but I have always wondered about this, and it seems to be the sort of question many of the people on this forum would be able to answer.

Thanks.