Around 38 minutes in, just after the Dukes meet with Roscoe and Enos about what they are going to do about Huey, you see Enos' vehicle from an exterior view coming down the road and the officer inside (Enos) clearly has on the black jacket. But when they immediately go to the interior shot of the vehicle where you see Enos driving he has on just the blue shirt.
Jesse makes mention to Bo and Luke at one point that Hughie might have changed his devious ways, since the boys haven't seen him in some time. However, he was acting sheriff of Hazzard County in an episode the previous season.
The junkyard-crane's vehicle-lifting device is identified as an electromagnet, yet it clearly has no electrical cable wired to it.