A Look Into the 23rd Century (1976)
https://www.youtube.com/watch?v=wMx6ToStHms&list=PLYn2a0e2FVIJ66EP8vMU64l-kIhHU9zg7&index=9&t - from the Behind The Science Fiction YouTube channel (9 mins long).
The blurb:
“A promotional short giving a behind-the-scenes look at the making of the science fiction film Logan’s Run (1976).”