G.D. Spradlin
G.D. Spradlin appeared in numerous Dragnet episodes. He played a phony cop selling NALE cards to morons, and he also played a tractor salesman who tells Gannon that he knows Joe and Bill just came to the convention to drink and play cards and chase women. That wa the episode about the crooked card games.
In real life, Spradlin was a lawyer who worked in the oil business and then started his own oil company and became rich, as a kind of real life J.R. Ewing.
He got involved in politics and didn't even try acting until he was 44 years old.
Quite an interesting guy behind the actor.