The Trio's version is interesting. Per the Bear Family book, it was recorded on September 11, 1963. On November 20, 1963, the Trio recorded it again, this time with Bob doing the lead. The second version sounds incomplete. I seem to remember that changing "Alberta" to "the mountains" was a common attempt to Americanize the song, but it drove Tyson nuts.

On the version with Stewart singing lead, did you notice that Stewart seems to be missing from the chorus?