The 1975 Pontiac Firebird in gold is used by Jim Rockford throughout the first 48 minutes of part 1. When Jim Rockford and Rocky plan to use the car to go to dinner it is still the same vehicle if one notices the rear full width tail lights. When they change their minds and decide to eat at a restaurant around the corner, the 1975 vehicle is suddenly replaced by a 1970 1/2 Pontiac Firebird in gold which has much smaller 7" wide tail lights. This 1970 1/2 is the vehicle blown up at the very end.
The 73 light green Monte Carlo is missing the left front wheel cover. Later it is the left rear wheel cover is missing. Even later the two men working for Hammel, actor Scott Brady, pursue Rockford in a squealing car chase about halfway through, they quite noticeably lose their left front hubcap when executing a reverse, sending it bouncing down the street, so at this point both left wheel covers are missing. But when the chase comes to a halt in the parking garage and Rockford cuts the valve from that same tire, the left front hubcap is still there.
The truck with the license number 35 662M is hijacked more than once, first by the guys in the red Cadillac convertible, and later by the silver Ford Elite. The truck hijacked right before Jim finds Lo Salvo's body has the same stickers behind the driver's door, the same wear marks on the logo on the door, and the same loose vent on the front.
In part 1, when Rocky goes into the diner, the guy following him in the Monte Carlo parks and then stands by his vehicle and remains there. However, from inside the diner you can clearly see his car but he is missing in every indoor shot. So also is the black rig parked perpendicular in front of the diner (it disappears in all the inside out-the-window views).
The Pontiac Firebird is a 1975 model (turn signals in the grille next to the headlights) in most of the scenes. When the car is shown driving at night, it is a 1974 model (turn signals down below the front bumper). Then in the daylight, it become a 1975 model again.
Hamill's thugs are searching for Rocky, describing him as an old man wearing dungarees, but Rocky was actually wearing what appeared to be beige dockers.
When Jim is roughed up by the two heavies, you get a rare look at the back side of the trailer. From that angle, it's obvious that nothing is hooked up to it for living in. No water line, no sewer line, no electrical, and no phone line.
Mary Ramsey states that Rocky hasn't missed one of their Saturday afternoons in ages. It's inconceivable that Rocky hasn't gone away on a weekend trip with Jim all that time.
At around 23 minutes, two men in a beige car are chasing Jim through a car wash. As the cars exit the car wash, you can briefly see a cameraman walk out from behind one of the stall dividers while he films the cars turning onto the street.
When Rockford and Dennis Becker (Joe Santos) are walking through the warehouse, the camera tracks them as they walk. As they walk in front of a large packing crate, though, the shadow of the boom microphone becomes visible and also follows them.
Mary Ramsey tells Jim to look for Rocky at Western & Pacific Trucking. Cut to the company sign and it says Pacific & Western Trucking.
During the first hijack sequence the trucker keeps looking towards a rear view mirror in the cab but with a trailer behind him a rear view mirror would be useless.