Plot hole: At the end of the episode, KITT has to travel about 45 miles in under 8 minutes. That means KITT would have to travel a little under 360 mph for the entire time. KITT couldn't travel that fast until season 4 when he got Super Pursuit Mode, and we never see the speedometer read that high even once.
Continuity mistake: After the photoshoot Michael and Lisa are walking. Lisa's dress is on her shoulder, next shot it's off her shoulder and the shot after that it reappears back on her shoulder.
Answer: I would say that unless there's visual evidence it was another K.I.T.T. car, as in you could see the bar scanner or cut steering wheel, people on here would correct the mistake by saying more than one 1982 Pontiac Firebird Trans-Am was sold and there's no reason it's meant to be a random car.
Bishop73