Ha ha, Dave McClain uses the database to authenticate M1Cs for people who ask... either they fall into one of the clearly defined serial blocks we have identified or they don't. Once in a while a guy will ask on a gun he has already bought, and Dave has to tell him its authenticity is 97% unlikely. We have tabulated some outright fakes, but usually it's just one of the 2.9% of numbers that fall outside a known group. Sometimes they get angry at him and tell him in no uncertain terms he is wrong :)