Oklahoma! was absolutely shot in 70mm TODD-AO at 30 frames per second. There are so many references online that I won't take the time to post any links here. A little time on Google.com will provide a plethora of results.
Dear RAH:
Did you see the 30-fps version or the 24-fps version?
(I became a huge fan of yours in high school after witnessing the original restoration of "Lawrence of Arabia.")