Does anyone know if "Out on the Western Plains" may have been a very early blues? I know a goodly amount of cowboys were black and the song is surprisingly blues-like right down to the AAB lyrics.

I was looking at "Pretty Polly" but it apparently can be traced back to Scotland several centuries ago and so it's blues-like nature is coincidental. But I'm not sure about this cowboy tune, which I learned from listening to Lead Belly. I don't know where he learned it.