You might need more to go on? You say Tipperary is there a reason you say that, did they quote this on a record in the US?
Do you know where they married? American marriage records were more detailed at the times you mention. In Ireland the record would be X = Y and two witnesses, maybe three. the register of a named parish and possibly a local townland name might be given.
In my experience marriage ages if used to predict birth ages are the most varied from the truth and death records next because no one needed to know their birth date until they emigrated, so be flexible? If you have good, consistent dates it might help. If they were from the mid-west of Tipperary, that is now Limerick county and may help with your search.
I tried a Mic* Co* and Margaret (plus variations) B* search and came up with nothing like your search names for an RC marriage in Ireland. However, not everyone was RC. Also, many second pairings were never married officially in church. As many as 40% "marriages" had no record associated with them for one reason or another.
Hope there is something here that helps.