The term "canon" seems inappropriate to folk music, a basic attribute of which is that its lyrics, arrangement, and even melody, are constantly changing.

And hey, folks, don't give the kid grief about the "obligation" of "[making] appropriate comments" and "[thanking] those who have taken of their private time to respond to your questions." People respond here because they want to. Besides, the guy posted his question less than a day ago; perhaps he hasn't been back yet to check. Ease up a bit.