Is there a term for a commercial song, in a folk/roots style, which gets accepted as an authentic folk original ?
I'm thinking of a song like The Wheel of the Wagon is Broken.
Country/Western Swing fans may know the version by Patsy Montana. Likewise Roy Rogers, Milton Brown, Sons of the Pioneers....
But there are more rootsy versions also, for example Caribou Bill.
Being accepted as a folk original means that performers feel free to embroider the various loose ends in the lyric with their own added verses, like you would with a folk song :
for example , Caribou Bill adds a verse addressed to "Old Faithful", the horse:
So long, Old Faithful
We've crossed the great divide
So long, old Faithful
there's other trails to ride
or Arthur Young, who adds more detail about the "old grey mare":
The old grey mare is missing
and there's weeds round the old ranch door
The wheel of the wagon is broken
It ain't a-gonna turn no more
The song's composer Michael Carr is an interesting topic in himself, likewise the co-credited composers Elton Box and Desmond Cox who were really the song's publishers. Carr was a resourceful commercial songwriter, working in Denmark Street, London's "Tin Pan Alley" for many years.