Colt 1911.45 ACP Production Statistics and Serial Numbers 1911.45 ACP ProductionMilitary Versions from 1912 to1945.Manufacturer/Serial Number/Date MadeBeginning of M1911:1) Colt: S/N 1 to3190 = Apto May 31, 19122) Colt: S/N 3190 to 7501 = Ma圓1, 1912 to Oct.