"This would suggest a non cowboy origin?"

I seem to remember reading and hearing a few years ago that real cowboys (unlike their Holywood incarnations) were unlikely to have been All-American boys, and that there are several cowboy songs in Gaelic (no doubt there were some in Irish as well). I also have vague memories of hearing that c50 per cent of them were black.

And on the cassette of Texan field-recordings "Sing Me a Song" edited by William A Owens (University of Texas Press) quite a few European nations are represented.