Hardly unmistakable but... Sparling (1890 or so) quotes Charles Gavin Duffy (mid-19thC) as believing it was probalby relatively contemporary with the WIld Geese incident.
To me, the problem with the War of Independence dating of the American version is that it predates the mass migration of people who would be likely to carry it. It just doesn't sound like the sort of song the Ulster-Scots would have brought with them - apart from the other obvious problem. I look forward to being contradicted by the LOC!.
p.s. I'll have a look for Horncastle in the Irish Traditional Music Archive when I get a chance.