Jimmy - October 14, 1964 - S2-E8
Factual error: The episode is set in 1964. When Frank and Jimmy first arrive at the dock and some of the dock workers are harassing Jimmy, there is a nice set of period appropriate cars in the foreground that the other dock workers are around, but in the background we see street traffic with 1980s cars driving by. (00:10:50)
Piano Man - November 10, 1985 - S3-E15
Continuity mistake: The old Ford pickup Sam steals to chase them is noticeably different than the one we see being driven later, including the front end, side, and roof damage, different side mirror type, no antenna on driven truck, and a different license plate number. (00:35:50)
What Price Gloria? - October 16, 1961 - S2-E4
Continuity mistake: When Sam goes out of the window to save Gloria, part of the ledge breaks off, but in the near shots it is broken off almost to the corner near Gloria, while in the shots from below most of the ledge is still intact. (00:35:45)
Answer: In the finale, Sam leaps back to the episode "M.I.A." which is set in 1969. Originally, he failed to stop Beth from remarrying. However, the episode you're talking about, "The Leap Home", takes place in 1970. At the end of that episode, Al tells Sam that Maggie, the woman who took the picture of Al, finally got her Pulitzer Prize posthumously. But there's no indication when the picture of Al becomes public, or if Beth even saw the picture. However, if Beth did see the picture, or is aware Al is a POW, she's already moved on.
Bishop73