Studebaker owners are very fortunate, indeed, to be able to have access to such records. From experience I know how Mopar and other Brand X owners get so extreme for originality. I owned a '69 Corvette L71...427 435 hp convertible and was fortunate to have its original sales invoice, window sticker, copies of all prior titles, complete service history of the car and the broadcast sheet from on the gas tank. That was an uncommon thing to own a car that was maintained as it was plus all its records. No knows whether Chevrolet has records for them anymore...they disappeared long ago...either lost or destroyed.
It's well recognized within the Corvette world that if those records were suddenly found and people had access to them there would be many unhappy current owners as they would find out their "all original" and "correct" Corvette left the factory in a completely different configuration. It's already generally acknowledged that there are more "original" big block Corvettes extant than ever left the factory during the big block years. Having the original records found would be a disaster for the Corvette hobby.
Pontiac owners generally do well as the factory records for them are pretty complete and available.