The Trans Am at Selleck Motors most likely wasn't used in the making of Smokey and the Bandit. The most telling sign of this is that the interior is golden brown, and not dark blue which was the color of the interior in the original Bandit car.
While trying to convince "Paxton Harding" to purchase a vehicle, "Don Ready" suggests he take his band on a tour of the Florida Panhandle. The first city he mentions in Gainesville, which is located North Florida, not the Panhandle.
During the scene where Don is making a tandem skydive into the Selleck dealership, there are a number of obvious mistakes regarding the parachute gear: You can see there is no main parachute connected at the "three ring circus" connector point on the main harness as the two are in the aircraft doorway; There is no drogue parachute used during the freefall; Under canopy, there are only 5 or 6 straight cords connecting the parachute to the harness, instead of 10 to 12 split lines; The parachute the two land under is very small (less than 200 square feet), instead of the 400 - 500 square feet required for a tandem rig; and when Cessna Jim pulls his parachute up after landing, it is not connected anywhere to the harness.