So yes....that makes alot more sense now.
So the only related question I have is in terms of the production of these "no size" Goodyear tires. I think Ford stopped using the no size tires on Mustangs towards the end of 1969. But did Goodyear continue manufacturing the "no size" tire into the early 70's? Were consumers at the time able to purchase these tires from their local distributor?....I assume they could.....and that is why some tires have date codes into the early 70's.