J.R. and Sue Ellen were married on February 15, 1970.
The wedding invitation that J.R. shows Sue Ellen gives the date of their second wedding as December 3, 1982. The relevant episode The Wedding (1982) aired on that day.
This was the first part of a two-part crossover with Knots Landing (1979) which ended with New Beginnings (1982). Both episodes aired on October 29, 1982. This marked the only time that episodes of Dallas (1978) and Knots Landing (1979) were originally broadcast on CBS on the same day.
This is the last episode until the series finale Conundrum, Part 1 and 2 (1991) to feature all four of Jock's sons: J.R., Bobby, Ray and Gary.
This episode marks the final appearance of the "real" Gary Ewing (Ted Shackelford) in Dallas (1978). Although Shackelford later appeared in The Family Ewing (1985) and Conundrum, Part 1 and 2 (1991), the events of the former episode (and the remainder of the ninth season) were revealed to be a dream experienced by Pam in Return to Camelot: Part 1 (1986) while his appearance in the series finale was part of an alternate reality in which J.R. was never born.