Yes, Kurt Russell had two roles in Gunsmoke. In 1964, at the age of 13, he played Packy in the episode Blue Heaven. Ten years later, in 1974, he played Buck Henry in the episode Trail of Bloodshed.
Gunsmoke aired for twenty years, from 1955 to 1975, with 633 episodes. It is still the longest-running prime-time drama; however, Law & Order ran for the same number of seasons, but only aired 456 episodes.
Kurt Russell started acting at an early age. Walt Disney signed him to a 10-year contract when he was only 7 years old.
View Kurt Russell filmography on IMDb.