Wanted: Dead or Alive had a similar episode where one twin was a killer and the other twin was getting the blame. The good twin/ bad twin stories have been done in a variety of TV shows and movies too. Have Gun took things up a notch, by twisting the usual result where the bad twin is brought to Justice.
In this story, Palladin gets hired by the good twin, Adam, to find the bad twin, Sam. Due to Palladin's cynical and suspicious nature, he thinks that it would be a joke on him if the bad twin had hired him to frame the good twin. So Palladin has his doubts about his client from the first moment.
Both twins are played by Brian Hutton, who had a short acting career of eight years, and then became a director, of nine movies. Hutton plays both brothers the same. They are both dark characters. That is why it is understandable that Palladin concludes that his client was the wrong brother. The result of Palladin's mistake is tragic for both brothers.
In the mix is Adam's wife, played by Jennifer Lea. Lea had a brief acting career, from 1956-1968. She has a shifty personality, and is clearly being dishonest when she tells the Sheriff & Palladin that Adam is Sam, the bad twin. Palladin believes her, instead of Adam, and lives to regret it. This is one of the best episodes, because for once, Palladin's cynical nature is the cause of a major tragedy for everyone in the story. There is also no shortage of gun-fighting and action.