A lot of labels used perfect die cut letters to put the master numbers and pressing numbers in the dead wax of their records. This is different than the hand written numbers that some companies used. In a lot of cases this can be used to a certain degree of certainty in determining a counterfeit with U. S. pressings. Some companies that had machine stamped master numbers were: RCA, Decca, Coral, Brunswick, Capitol. Columbia, Liberty, Laurie and Rust. Atlantic had the numbers usually hand written, but somewhere in the dead wax had AT machine stamped, but once in awhile it was handwritten.