I’ll bet every saddle in the movie is made of leather.
I remember 55 years ago when come company made a saddle made of plastic. I think it was PENNEYS when they sold through a catalog.
About that time there also came out a C&W song on the raido about saddles(but really was not about saddles)
“Don’t give me no plastic saddle,
Let me feel that leather when I ride.
Don’t give me no paint and powder,
Honey let me feel new hide....”