Birth of James Buckley

I am trying to locate any record (baptism etc) of my GGrandfather James Buckley according to Australian marriage records his parents were Richard and Mary (nee Garvey).  I have a birth date of 27 July 1853 this matches with Shipping record to Australia arrived 1869 age 16 which makes 1853 his birth year, but may be a couple of years out as on Marriage Cert. dated 1876 his age was stated as 28 which makes him born 1848? Death Cert 1905 states age as 56 therefore born 1849. I am at a total loss.

He was married as a Catholic but I have a feeling he was Protestant before coming to Australia.

Please help if possible.

Thanks,

Lance Buckley.