Given it's under a different name Always Rejoicing, and there's also a suggestion (link below) that the tune is derivative from a known shapenote melody, Sing,"Holy!" to the Lord of All, then we start to see folk tradition at its best at work.
Has anyone thought of looking in the Library of Congress?

https://books.google.co.uk/books?id=L_liCUHqZboC&pg=PA65&lpg=PA65#v=onepage&q&f=false