My ancester Michael Morgan was born in 1833 and was a plasterer by trade. I do not know the Roman Catholic Parish he came from but family oral history states he was from Sligo. He went to England to work and eventually emigrated to New York, where he continued to work in his profession.
Most of the RC parishes in Co. Sligo have records starting later than 1833. I checked the subscription site Roots Ireland and there was an 1824 John Morgan baptismal record but that John was Church of Ireland.
You may want to consider DNA testing.