The RC records for Clifden parish start in 1838. From your note, it would appear that Bartholomew and Bridget were born pre-1835. To be sure I did search the subscription site Roots Ireland but did not find a Bartholomew Griffin record in Clfden and the earliest Bridget Mannion baptismal record was in 1854. Likely records are not available.
Have you considered DNA testing?
Please consider adding Bartholomew and Bridget to our XO Chronicles site for Clifden parish.