Trafton shows a tattoo which he said while serving a 10-year sentence at Folsom Prison. Folsom wasn't built until 1880, so this episode would have to take place in at least 1890, but is supposedly set around 1873.
Festus tries to tell a joke throughout the episode but is always interrupted before he can deliver the punchline. The set up is a group of cowboys have told the same joke so many times that they have decided to condense them to numbers rather than tell the joke. A new hand is trying to get in on the fun but isn't sure what is going on. Each man yells out a number and the group breaks up in laughing. Festus is about to tell us what happens when the new guy tells a joke. The punchline is: He shouts out a number (let's say it's 52), and the group fails to laugh. He is met with silence, and is confused, so one of the group tells him - "It's not the joke, it's the way you told it."