Near the beginning of the story, Uncle Jesse states that he is going to ask for a loan to fund Bo and Luke's race car project because the drought has resulted in less crops/income. Yet later in the story when Bo and Luke are being chased in the General for the first time, they take a road that is closed, stating it is closed because the bridge is washed out. Drought/flood continuity.
In the early seasons, Lost Sheep, Bo Peep and Shepherd weren't being used as call signs on the CB, but they are in use during this flashback episode.
When the couple looking for the car that would become the General Lee talks to the junk dealer that sold it to the Dukes, he calls it a "beat up, black '68 coupe." The General was actually a '69.
The truck the boys are driving before they build the General Lee is not old enough to be the ten year old clunker that Uncle Jesse describes.
This episode's title is silly and misleading. A car can't have a birthday. It should be considered an anniversary, not a birthday.
Although most of this story takes place in 1976, Boss Hogg's car, the " Hogg Hellcat" is a 1979 Chevrolet Malibu.