It does say that in the Roud index. I'm just trying to reconcile that with her recorded statement that "this song is as old as the hills." I couldn't find a copyright for it from a reputable source, but to be honest the search tools aren't good. (There is a sound recording copyright issued to a large collection of many artists, but not an actual song copyright.) However, the pre-1978 copyrights are not digitally searchable, so it's possible (even likely, given that there must have been earlier recordings) that there was a registered copyright earlier. Whether that's an actual song copyright is another question. And not everyone is careful about registering copyrights.

I figure there are three possibilities - (1) she wrote it and for whatever reason chose to say it was an old song, (2) it's a song from her family and she claimed it mainly to keep someone else from stealing it, as Jean Ritchie used to do for her family songs, or (3) it's an old song which she substantially reworked to the point where it was essentially a new song.

In any case, the song clearly came through her if not from her, and she gets full credit either way.

Dan