There were two styles of tires used on a 1969 Z/28:
Goodyear Wide Tread GT E70 x 15
Firestone Sport Car 200 E70 x 15
Both are available in reproduction. The repro Goodyears are physically larger than OE and are polyester cord, originals are nylon cord. The Firestones may be off the original tooling.
At this time no 1969 Camaro is known to have been built with Goodyear Polyglas tires.