One thing I noticed was a Star Trek fan extra who snuck in the Vulcan salute at the end! Have you ever seen it? Watch at the end when the young people are reaching for the old man... right in the foreground, one of the raised hands briefly makes the Vulcan hand sign, and it made it in the movie! See my screen capture of the moment below...
UPDATE: I have heard from the person owning the hand in the above scene! I received an email from Adam Wyse, who wrote this:
Thought you might be interested to learn that I was the Vulcan Hand Salute kid in Logan's Run. My mother was a talent agent in Dallas after we moved here from L.A. in 1970. I had done many national commercials through an agent there and my mom decided to open an agency in the new film frontier of Dallas. As a result, she always sent me on extra calls for films made in Dallas at the time like Logan's Run, Phantom of the Paradise, Semi-Tough and others. I remember working weeks on end on LR culminating to the big finale of filming the destruction of "Dome City" filmed at the Ft. Worth Water Gardens. We were directed to wait on the far side of a wall for the explosions and then came over to gather around the first old person we'd ever seen, played by the late Peter Ustinov. I also remember a girl from our agency was selected to be the one to touch the old man's face. Rumor has it this required a "special audition", but who really knows. Anyway, I was simply wanting to find a way to locate myself in the crowd and didn't do it long, I thought. I feared it would get noticed and end up on the cutting room floor, but as you mentioned, made the final print. I had forgotten about this until a friend of mine from back then called me and said the salute had made the Internet. So, there it is and thanks for the applaud.
Isn't that cool? Thanks, Adam, for sharing your story! It is neat finding out all these years later who that was that made their mark for Star Trek fans in a sci-fi movie!