Both of these guys were from, or associated with Glasgow. Ewan McVicar (excuse spelling) has written about each of them in "One Singer One Song". I'd guess that they did not specialise in Irish rebel songs but happened to sing a few...

They're before my time, but I'd guess late 50's into the 60's. I'll check my copy of the book and try topost more info if I can find it...

Cheers