On the off chance anyone responds, why do you think that the year 1849 is inaccurate? it was a peak year of Irish immigration, and the only evidence that it was 1749 is from song collector's anecdotes and theorizing. Those song collectors, English and American, held the anti-catholic sentiment of the time and so making it 1749 would imply that the song is English or "scots" (protestant) Irish. They would also have liked for their song to be "old" by their standards. Also, you can find the word "freeholder" on contemporary legal documents in Ireland. I think it's a famine-era ballad related to the older "Bunclody" from County Wicklow. Here is a link to an article about County Wicklow during the famine:

https://www.independent.ie/regionals/braypeople/news/wicklows-suffering-during-famine-times-37953727.html