The only gun law there was in 1963 was the 1934 National Firearms Act which called for taxing gun sales and the reporting of interstate gun sales involving certain kinds of weapons, but not long infantry rifles. And the reporting had to be made to and kept by the Treasury Department, not the FBI.
So, there was no requirement to report gun sales to the FBI in 1963. So, how did the New York office of the FBI come up with the history of that rifle so fast from just the serial number?
You can't tell me that someone actually recognized the number. That is preposterous. But, how did they look it up? There were no computers. There were only paper records, and the FBI didn't have any. The Treasury Department did, and they weren't called. So, how did the New York office figure out so fast that that rifle was in the inventory of Crescent Firearms and was shipped by them to Klein's Sporting Goods in Chicago in 1962 or early '63? I am not buying it.