Rescued Dog

When I started to clean and prepare our B61 for painting, the original brown undercoat was in good condition and I was surprised to find various markings at the front of the chassis rails. There are stenciled markings which I can't identify. I wonder, did Mack press the rails in which case they stenciled the markings or were they purchased from an outside supplier who applied the brown primer and stenciled the numbers on? Also there were hand written numbers painted on above the stamped chassis number. As per the Chassis Sales Record these turned out to be the CSC numbers, so would have been put on when the chassis went on the assembly line. The B61 had a factory finish date of December 20,1963 and was shipped to Mack Australia in January 1964. Neil