“The Devil's Rain premiered in 1974.”
Wrong
Correction
Shot in late 1974, released in June 1975.
Shatner's 2019 tweet said the film "premiered in 1974." It was filmed in Durango and Mexico City in late 1974 and released in 1975. The slip doesn't change his point about the 1975 mask.
What people actually said
“The Star Trek mask was created & sold in 1975 and Devil's Rain premiered in 1974.”