Victoria Principal refused to appear in the final episode because there was a good chance the show would return the next season. She said she would only appear if she were 100% sure that the show wouldn't return.
Several former cast members returned for the final episode including Linda Gray, Jack Scalia, Ted Shackelford, and Joan Van Ark. Victoria Principal was also invited to participate but declined.
Larry Hagman (J.R. Ewing), Patrick Duffy (Bobby Ewing), Ken Kercheval (Cliff Barnes), Linda Gray (Sue Ellen Ewing) and Steve Kanaly (Ray Krebbs) are the only actors to appear in both this episode and the first episode Digger's Daughter (1978).
This was the first episode of Dallas (1978) in which Joan Van Ark (Valene Wallace) appeared since The Split (1981) almost ten years earlier.
Of the characters brought back for the series finale, Nicholas Pearce (Jack Scalia) is the only one who made his debut after Season Two. He first appeared in the Season Eleven episode After the Fall: Digger Redux (1987). Although neither Ted Shackelford nor Mary Crosby appeared in Dallas (1978) until Season Three, their characters, Gary Ewing and Kristin Shepard, made their debut appearances in the second season, in which they were played by David Ackroyd and Colleen Camp respectively.