Chronologically, this is the earliest leap within Sam's lifetime. He was born on August 8, 1953, four months after the events of this episode.
Season 1 ended with this episode.
But Sam's leap out of this episode is into a female secretary; that episode was broadcast as the 4th of season 2 ("What Price, Gloria?"), instead of a continuation of season 1.
Al: Sam...you know, Allison could be the killer.
Al: No? Why are you saying no? (reading) Because her body could part the red army?
Sam: No. Because we've got Clapper.
Al: Careful, Sam. There was no cure for that in 1953.