The Road Runner shown is a 1970 model, not a 1968/1969.
Two different models of cars in Richard Petty #43 STP livery are shown, one a 73-76 model Charger, the other a 1968-69 Road Runner.
The red lights on Ponch and Jon's motorcycles flash alternately instead of one on steady burn and the other flashing as required by California vehicle code and in consistency with the rest of the show.
Shortly before Ponch and Jon pull over the gold truck, a red Volkswagen bug convertible is behind them, which is close than far away and then close again, depending on the shot. When a rear view of the truck is shown, right before it pulls over, the bug is up ahead.
After Ponch and Jon have pulled over the gold truck, they do so right next to an exit ramp with one of the cars exiting being an orange Ford Pinto. Then, when the green Chevrolet speeds by, the guys give chase and the same orange Pinto is now back on the interstate with them.