If you have received your NCRS shipping data report, or your dealership that sold your car new is known, then I have a suggestion. Most Public libraries have the town newspaper on microfilm and with very little research time, you could find many ads by your local Chevrolet dealer, complimenting your cars history and paperwork. In most cases the quality of the copy machines at the library would be sufficient to make a suitable copy for your records.
Below are two examples of the dealership that sold my 69 Z28, C. D.King. There were many other ads by this dealer for other cars, Chevelle's, Corvette's, etc. These two were all I found with Camaro's listed. Denton-Smith was another dealer locally.
For some, this may be a long shot. But you might be surprised.
Thanks Darrell, for posting the ads.
Good luck,
Bryan