I've heard a slightly different first verse, instead of:-

...The gaugers all, from Donegal, Sligo and Leitrim too, Oh we'll give them the slip, and we'll take a little sip of the real old mountain dew....

I've heard:-

...The gaugers all, from Donegal, Sligo and Leitrim too, May they rot in Hell, May they never get a smell of the real old mountain dew....

Perhaps the singer of my version had had a run in with Customs?

Regards

Walrus