Try to realize that people who make a living stealing are "professionals" this was'nt some sort of genius master crime years in the making. Gun Shop thieves regularly drive trucks thru doors, steal heavy equipment and remove any and all obstacles. Gun shop thefts are quite common nationwide. In 2014/15;  12,000 firearms were stolen from 1,100 federally licensed dealers. As for serial numbers, good luck with that! remember congress prevents the ATF from maintaining a functional database,ie. no computers; besides these crooks didn't steal these guns to resell to pawnshops or on aklist, they stole them to supply the  criminal element with firepower!