Lee was still claiming credit for Gardner's song in when he wrote "Cowboy Songs" in 1938.
He heads the sheet music "Words and Music By Powder River Jack Lee on Victor Record 23527."
He did mess around a bit with Gail Gardner's words, with a new title "Tying a knot in the Devil's Tail" (see thread 13471 for "Sierry Petes").
Attribution to Gardner has not yet been made in the DT, nor have Gardner's lyrics been added. Music should be attributed to Simon.

Getting back to "Red River Valley," none of the suggestions of provenance nor claims to authorship have been verified.