Thanks very much to everyone who found and posted this! RAH sounds very "Missouri" in his accent in 1949, to me. There is 13 seconds of his famous "Year One" Apollo 11 moment here: http://www.sffaudio.com/?p=17220
and twenty years later he sounds just a little more West Coast, though basically the same. I wonder if others would agree. Anyway, it was a thrill just to see the film.