Technically the fiberglass belted F70 x 14 RWL tires did not become a Camaro option until the April 2, 1969 revision of the dealer ordering sheet as RPO PL4 which was a $26.25 option on Camaro SS.
You cannot tell from the pictures but I do have F's on the front and H's out back, so yes absolutely not factory original.
I like the Polyglass look and the car has good stance too-as a driver it scratches the itch just fine.