I didn’t realize Festus didn’t join the cast till Season 8. So was Chester (Dennis Weaver) the side kick up until that time?
I read a Wikipedia entry that said they had considered Denver Pyle for the part of Dillon...he was a good bad guy in this episode, can’t have imagined him as Dillon.
I’m not 100% certain, but I recall it working something like this: Dennis Weaver made a pilot film or two. He was expecting to leave, but the pilots didn’t sell, and he stuck around, in fewer and fewer episodes for about a season or so. Burt Reynolds (as Quint, the blacksmith) was apparently added in early season-8, to pick up the slack of the gradually departing Chester. Around the same time, Ken Curtis made his first Festus appearance, but he didn’t really become a regular right away. Just made a few follow-up appearances for a year or more, but eventually eased into a full-fledged regular. None of it seemed a very clear-cut ‘replacement’ transition, in terms of these three sidekicks. And I even think there was a single episode or two which featured ALL three, Chester, Quint and Festus.
He remained the side kick until 1964, through 305 episodes (this from IMDB).