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The RC records for Kilfree and Kiilaraght parish start very late--1873 so no baptismal record would exist.
I looked at the 1827 Tithe listings and there were two records for a Mathew Sherlock in Kilfree parish. One was listed for Doon East townland and the other for Carakeel or West Doon. Between the two plots, he had a little more than two acres of land that he was leasing.
I think both records pertain to the same person and based on your message maybe this is the father of the Mathew who was sent to Australia.
The 1858 Griffiths Valuation head of household listing for Kilfree parish shows a number of Sherlock records including a Mathew. https://www.failteromhat.com/griffiths/sligo/kilfree.htm
Let me know if you have any questions.