I appraised the car when Jim had it and it did come from Jerry B with what were said to be the original tires, and those tires are some vintage Goodyear Wide Tread GT, size F 70-15. Even if the date codes come up right, I would wonder if they weren't dealer swapped from a Yenko Chevelle or something. Check the dates on the wheels, compare them to the car and the tires. We've all come across wheel swaps done at the dealer for buyer's request or to replace stolen ones.
There wouldn't be any reason for a Camaro plant to have that size tire in stock (Although I guess you could argue the same about the L-72 engines and BE rears..)
Its a bit troubling to hear about the misplaced tires (glad they're found). PLEASE tell me it still has all of that cool documentation Jerry dug up and Jim preserved.
(Hopefully Dave C. is using this treasure hunting opportunity to fill the trunks of the auction cars with all of the "stuff" he has for them.)
Good luck on your fact-finding mission, Les.
TOM