Brochure cars and some press cars could easily be "incorrect", airbrushing in details, using previous-model parts, or for that matter parts that would later be recalled.
Reference the '71 Challenger T/A photo, the heavily airbrushed '69 & '70 Plymouth brochures, the "recall wheels", etc.
Manufacturers were much more concerned with promoting the new models and moving units than how accurate those portrayals would be 50 years later!