The 'Streets of Laredo' & 'My Home's In Montana' are definitely different, though similar, melodies. As Alice said in the related thread, the melody is about the same as 'Molly Malone'. The melodic contours of these 2 songs are very close.

I remember liking all three songs from the first time I heard them, possibly because of the similarities. 'Molly' was probably the first I heard, then 'Streets', then 'Montana' all when I was a young whippersnapper in the 1950s. I must say that I did not equate the melodies of 'Molly' with 'Montana' until I read Alice's post here.

Cruiser