In the snack bar parking lot: the same people from previous scenes are sitting at the snack bar. Also, the same cars in parking lot from the previous hotel and TJ scenes include the gold Mustang, gold AMC Ambassador, red Cadillac, orange sports car, and the white sedan with fins.
In the scene with TJ on the street: the same cars are passing in the background repeatedly including the gold Mustang (white top) and the gold AMC Ambassador (black top). Other cars seen parked or going by in this scene and the snack bar parking lot scene include a silver Buick Riveria, red Cadillac (white top), orange Opel, and a white sedan with fins. Additionally, the same people are walking back and forth in the background including the lady in the pink dress who passes by at least 6 times.
In the scene at the Hotel Dorado: the gold Mustang is now parked in front of the hotel along with the gold AMC Ambassador just seen in the TJ scene. The white sedan with fins also passes by. Also, some of the same people from the TJ scene are now walking in the background.
When Malloy dials the phone to report the DB, he only dials 3 digits - not 911. 911 service was just being established in 1968.