The Carroll of Ely Coat of Arms is real (see http://clancian-ocarroll.com/html/arms_of_the_o_carroll.html
). There were other known Carroll septs that had their own Coat of Arms, in particular Carroll of Oriel. Unfortunately, that clan was eradicated by the English Normans circa 1167 and erased from history. Irish Arms or Titles did not exist from the point of view of King Edward VI and subsequent English Monarchs. In fact, an Act of 1587 stated that all Gaelic Titles would “henceforth cease, end, determined and be utterly abolished and extinct for ever." See http://www.carrolloforiel.com/the-arms-of-the-carroll-of-ori...
The reason Carroll of Ely survived and was recognized in 1587 is due to various marriages between the Carroll of Ely and English royal lineage. First marriage with Richard de Clare "Strongbow" (2nd Earl of Pembroke born in 1130 led the 1130 Anglo-Norman invasion of Ireland in the reign of Henry II), married 1171 to Aoife Mac Murrough Princess of Leinster, descendent of Brian Boru and other members of the Carroll of Ely. Second marriage in the late 1300's, Carroll of Ely Chief Teige Carroll married Joan, daughter of James Butler, the Second Earl of Oremonde, who was the great grandson of English King Edward I. Third marriage in the early 1500's between Carroll of Ely Chief Ferganainm (Mulroney the Great) to Elizabeth, the daughter of Gerald, the 9th Earl of Kildare, and Elizabeth Zouche co-heiress of Lord Grey of Codnor. It goes the other way too; daughters of the Carroll of Ely married into the English royal lineage.
By the way do you know where in Ireland your Carroll's came from?