The Mercedes chasing Jim and the comedian contains two people. There is clearly an empty back seat in several shots. Then after Jimmy pulls over to the police stop, the Mercedes pulls up to a pay phone. A third mobster is then seen climbing out of the back of the car to make a call, returning to the back seat and shooting the front seat passenger. (At the start of the chase, a third person is visible in the rear seat.)
In speaking with his police contact Becker, Rockford says, "Joe, things are finally beginning to make sense," using actor Joe Santos's name, not his character's name, Dennis.
When Rockford and Beth are leaving the police station, Beth closes the car door on her dress.
When Jim goes to Russo's, it is supposed to be night time, but there are obvious shadows in the street.
As they leave the police station, Beth and Rockford are talking to Becker and she says she is late for a court appointment. Dressed as she is? The 1970's legal profession was a bit more formal in dress, especially in court. (Note: Presumably, Beth was going home first to change).