Hey, I just re-watched the episode where Jerry, Elaine & George go to the party on Long Island (I think the episode is "The Party" but not sure)...its the episode where Elaine makes the comment "..maybe the Dingo ate your baby"....anyways:
I just noticed that when they arrive at the party, George's "girlfriend" says "Guess what?! I just sold 129 West 81st Street." Correct me if I'm wrong, but isn't that Jerry's building???? Jerry would surely have heard the comment and would have said SOMETHING about the fact that his building had just been sold don't you think?