The hand that strikes the match to begin the opening theme sequence is different from the original that's been used throughout the series to this point. Also the match is now blue instead of red.
The name Whitmore Channing may be a reference to real life Soviet spy Whittaker Chambers.
Anyone now who sees the skinny audio tape used as video tape (for the fake news broadcast) would know it wasn't real video tape. But most people in the 1970s had never seen real video tape and would have never realized it was fake. It was only after people became familiar with VCRs that producers had to use real video tape for such scenes.
The plot of fooling Channing in to thinking he was unconscious for a full day was essentially repeated in the 1972 episode "Two Thousand" guest starring Vic Morrow. In the Morrow episode, however, they fooled him into thinking he was now living in the year 2000, a 28 year gap in his conscious memory. There was also a previous story where William Shatner was tricked into believing he had gone back into the past.
The keys thrown down to distract the guard have a Chrysler logo on the fob, but no Chrysler keys on the ring.