Actors that played past and future old west lawmen: Williams was played by Clu Gulager, who played Sheriff Emmett Ryker for 4 seasons on The Virginian (1962). Singer was played by Kurt Russell, who would go on to play iconic lawman Wyatt Earp in Tombstone (1993).
"Teenager" Andrew Stevens was less than 4 years younger than Kurt Russell. Stevens was in fact 20 years old at the time.