Welcome to the Stovebolt madness. There is no cure! shake
You are correct, VIN #s didn’t come along until several years later. Most GM vehicles were titled off the motor serial number so if it has the original motor you may just be able to file for a lost title. If not, every State has a process for retitling a vehicle.

Martin
'62 Chevy C-10 Stepside Shortbed (Restomod in progress)
'47 Chevy 3100 5 Window (long term project)
‘65 Chevy Biscayne (Emily)
‘39 Dodge Business Coupe (Clarence)
“I fought the law and the law won" now I are a retired one!
Support those brave men/women who stand the "Thin Blue Line"! Hug a cop!
USAF 1965-1969 Weather Observation Tech (I got paid to look at the clouds)