The sheriff's car that is seen racing on the highway is not the same one that pulls up to the construction site just a moment later. The former appears to be a 1965 Ford Galaxie; the latter is a Rambler. Also, the one on the highway has only one emergency light on the roof; the latter has two, as well as a siren.
The Ford Mustang that is first seen parked on the street is not the same one that later pulls alongside Kimble. The latter has decorative striping on both sides of the car, and the whitewalls tires are somewhat different.
During the fight scene between Kimble and Mitch in Act IV, one can tell they used stunt doubles, with the stand-in stunt performers (especially Kimble's) being shown full face.
The "Slauson vs Ranson" boxing poster seen in two locations in the alley behind Frankie's Flower Shop is the same one seen in Decision in the Ring (1963) (aired two years previously and set in Los Angeles), and in The Good Guys and the Bad Guys (1965) (aired six weeks previously and set in Montana), and in Not with a Whimper (1966) (aired three weeks previously and set in West Virginia).
Kimble and Jan were able to hop into the box car easily because the sliding door is completely open. The box car door being open is highly unlikely given the fact that the car is carrying freight (the barrels that Kimble and Jane use to sit on after they get inside the car).
When the boys are reluctantly going through the mug shots the fourth picture in the stack is Kimble's mug shot. Mug shots are pictures taken when a person is booked into a jail. The only department that would have that mug shot picture is where that person was arrested and booked into jail. While other departments in other cities and States may have a wanted poster for a fugitive they would not have the mug shot picture in their mug shot files.