A copy of Kilby Snow's lyrics, on which the Grateful Dead's version was based, is here: Kilby Snow's version
Altan's seems to use some lines from old Scots copies in Child's collection, such as the making of the fiddle from her breast bone, and one or two lines they may have composed themselves. The whole business of the magical fiddle fashioned from body parts is interesting, as this part of the story had disappeared from most of the versions collected in the 20th century, which usually end with the miller pushing the woman back into his pond, and getting hung for murder. 'The Wind and Rain' is unusual in that it does include the fiddle.