Don enters the bar during the daytime but Bewitched is on the bar's TV. Bewitched was a prime time show in 1968 airing at 8:30 PM, and would not be shown by ABC Daytime and ABC Saturday Morning as reruns until 1973.
The apostrophe on the sign Pete backs into is upside-down, a typographic error not common until "smart quotes" were introduced on word processors after the show is set.
The skyline behind Peter's desk while he's on the phone clearly shows the Pan-Am building just a couple blocks away as if the office were still on Madison Ave. The Time Life building is not that close to the Pan-Am building.