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I searched on the subscription site Roots Ireland and did not locate a James Courtney baptismal record around 1808. The closest was an 1819 record in Cobh RC parish. Likely the record for your James is not available.
I did check the Tithe Applotment lists for Kilworth civil parish. There were a number of Courtney records primarily in Ballinrush townland.
You may want to add James' emigration story to our XO Chronicles site and possibly someone will see a connection. https://www.irelandxo.com/ireland-xo/history-and-genealogy/ancestor-database