That was the episode where Gary Crosby (I think) was playing an exploiting "song catcher" combing the Appalachians for "authentic" folk music he could commercialize and get royalties on.

I got the impression that the song had been written for that show, with the aim of sounding traditional. Am I right, or is it really either a trad song or a newer folk song that was written independently of Twilight Zone and Serling?