Here's something for you problem-solvers....
Car manufacturers start using VIN number in the mid-1950s, bur they were not standardized, even for any particular manufacturer, like Ferrari.
So, besides the chassis' individual serial number, did these cars have some sort of VIN? I was able to find some bits of information:
Chassis designations:
400 SA: 538 U 250 SWB/SWB Cal/GTO: 539 250 GT Lusso: 539 U
Paint Code:
Rosso Cina paint code: 20456 S
So if you wanted to build a USA-style of a VIN, you could. OTOH, each GTO was personally sold by the dealer to the owner, and probably new the owner very well, and there were only the few cars made, so if you if you needed anything, you didn't have to enter the VIN (into computer) to get a part...
But I'm still curious to see what there was at the time...