Sounds like Autry played all kinds of guitars in the movies, not just the old-fashioned small-bodied ones. He was, after all, at the forefront of country-and-western music.
A quick Google also reveals:
The Gene Autry Roundup guitar, introduced by Sears in 1932 and probably made by Harmony. This IS a small-body guitar, solid spruce top, solid mahogany back and sides. In 1932 it sold for $9.75! Looks like a nylon, but is actually a steel string -- narrow steel rollers, pegs in the bridge, etc. This is according to a commercial site I won't mention here...but there seems to be a lot of info all over the internet about these guitars.
One final note, small-body guitars in general are making a real comeback, they're available everywhere at all price points. The ones I've seen in the retail stores are mostly steel-string, but I've seen nylon strings too.