Wait a minute.
Bob Dylan likewise has another city in place of "Ireland." Given the late date of the Baez and Dylan recordings, my thought is, "That Don't Mean Nothin."
I frequently localize place names in songs depending on where I am and how much I like the place. I believe this is just a folk-ism, but as retrospective "history" it would be wrong for anyone to use that to argue for the provenance of the song. The logic was good, but the major premise is shaky.
Mad Maudlin--yes, but. Depending on how pure you aim to be, there is still a question of which version it was that was printed in 1858.
CC