Which three Gilligan's Island stars appeared on Gunsmoke?

Jim Backus (Thurston Howell III), Natalie Schafer (Lovey Wentworth Howell), Tina Louise (Ginger Grant), Alan Hale Jr. (The Skipper),

Dawn Wells (Mary Ann Summers), Russell Johnson (Professor Roy Hinkley), Bob Denver (Gilligan)

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...Jim Backus, Alan Hale Jr. and Russell Johnson...