Snopes found the rumor to be true, there really was a character on a 1950's Western that wanted to help save the town by building a wall around the town.
Here's the description from the show.
Walter Trump, a confidence man, puts on a long robe and holds a tent meeting in the town of Talpa. He tells the townspeople that a cosmic explosion will rain fire on the town and that he is the only one that can save them from death. Ranger Hoby Gilman attempts to prove Trump is a fraud.