With hands that were trembling I took out my gun, and aimed it at Shep's faithful head; I just couldn't do it, I wanted to run, I wished they would shoot me instead.

(from my early days of Elvis fandom - yes I know he didn't write it).

When I heard Archie introduce the song (not Old Shep), he referred to an Irish version with the "and my dog I did shoot" line as opposed to the "with my dog..." that he actually sang. Of course he might just have been having us on - that's showbiz. I had to ask him about the "canny goin' man" bit too. Exactly as LTS pointed out above.