Slim talked about this in his autobiography as there was always a discussion over how much of the song was the original by Dan Sheahan and how much was written by Gordon Parsons who "assembled" and copyrighted the version that Slim sang. If I remember rightly, he said that Gordon learned a fragment from someone, which would have been of the Dan Sheahan song, and wrote his song around it. Slim ended up good mates with Dan Sheahan and went on to record a few of his songs apparently which would have kept old Dan in beer money for quite a while. Back in the eighties and nineties, a song on a Slim Dusty record was reputed to be worth about ten grand in royalties.There was quite a famous court case over the tune which as mentioned before turned out to be close enough to Beautiful Dreamer for the owners of the Stephen Foster copyrights to win the case.