I think that is highly likely because so many did drop their prefixes. I know that my O' Bannons did. The "O" simply means "the son of" or "the clan of". So in my case my O' Bannon was the son of Bannon or of the clan Bannon. Cathy Psalms 108:1-4 "My heart is steadfast, O God, my heart is steadfast! I will sing and make melody! Awake, O my soul! Awake, O harp and lyre! I will awake the dawn! I will give thanks to the thee, O Lord, among the peoples, I will sing praises to thee among the nations. For they steadfast love is great above the heavens, thy faithfulness reaches to the clouds."(RSV)