Castlebar-John O’Malley/Malley

I have a very interesting new found brick wall.  My great grandfather, John J. O'Malley was born in Castlebar 12/29/1874 according to death records.  Other documents indicate he could have been born from 1865-1874. Family lore was he was an only child and his parents John OMalley and Mary Kane with both dying young.  I recently came across a civil birth record for a John Malley born 10/29/1874 at the Castlebar Workhouse to  Bridget Malley.  The reason this struck me as interesting is that that date the birth was registered was 12/28/1874 just one day difference from his death record date of 12/29/1874. I have never come across any marriage or information on John and Mary Kane Omalley.  There are birth records for children born to a Mary Cain and James OMalley.  These children emigrated to Cleveland Ohio where John  J Omalley died but have never been able to fully connect him to that line.  Would there be any way to investigate the Castlebar workhouse birth.  Thank you for any help you can offer