I don't remember how the episodes were originally shown, but, according to IMDb, it looks 'Carnival of Thrills' and '10 Million Dollar Sheriff' were screened back-to-back, but the two parts of 'Undercover Dukes' were shown a week apart. Now that we have DVDs, it doesn't make much difference as there's no waiting. The two-parters also let us have slightly deeper storylines.
Before anyone questions Mark's spelling, Rhuebottom's was sometimes misspelled Rheubottom's on the show, so the model is screen-accurate! Both spellings are visible in the screengrab below, which I first posted in the Hazzard Square thread.
Untitled by mommydawn2000, on Flickr
Untitled by mommydawn2000, on Flickr
Untitled by mommydawn2000, on Flickr
Untitled by mommydawn2000, on Flickr
And a new soda machine for teh garage!: Untitled by mommydawn2000, on Flickr