In this question the Star Trek dating scheme was discussed. It is well known that in the TOS episode "The Squire of Gothos""The Squire of Gothos", it seemed to suggest that the series was set some 900 years in the future, while in "Space Speed""Space Speed" the series was some 200 years in the future. Were any other times suggested in the Original Series? Potential possible episodes are: Series 1 "Tomorrow is Yesterday""Tomorrow is Yesterday", "City on the Ede of Forever""City on the Ede of Forever" and the Season 2 episodes "The Changeling""The Changeling" and "Assignment: Earth""Assignment: Earth".
Admittedly, some pertinent answers are given here, I just wondered about other episodes.