The CZ-38 was originally designed for the Czech military, which ordered 41,000 of the pistols. The Czechs never got to use their new guns, though, since the Germans had taken over the country (and pistols) before they could reach combat units. According to this translation of a Czech-language work, Ceskoslovenske Pistole 1918-1985, guns numbered 240000 - 242999 went to the Luftwaffe. Numbers B291000-B291999 (the B in front standing for "Bulgaria"), were for export to Bulgaria. The remaining pistols, with numbers 250,000-291,000, went to German occupation forces. These numbers are confirmed by Ian McCollum's brief article on the gun. In terms of finding out which serial number went to which squadron/soldier, I can't find any resources regarding weapon assignments. Your best bet would probably be to email Forgotten Weapons or some other firearms ID organization and see if they can help out. Hope this info's useful!