This is the third of three appearances Paul Genge makes in the series, each time playing a gangster of some sort. Classic film aficionados will note that perhaps his best remembered role as a gangster is in the Steve McQueen movie Bullitt (1968) where Mr. Genge plays one of the hitmen who dies at the end of the chase scene when the car he is in explodes into a fiery ball.
This is the fourth of four appearances Milton Selzer makes in the series, each time playing a different character. In a few years from the original airing of this episode, he would become more familiar to TV audiences with his recurring role as Parker in the TV secret-agent-spy sitcom Get Smart (1965).