thomas harrington/herrington/hethrington

My ggg granparents Thomas and Mary Herrington arrived in New York on  June 29 1840 aboard the ship Carroll of Carrollton from Liverpool.He was age 23 Mary about 24.In1846 they are living in upstate NY and he states in his naturalization papers that he is from Fermanagh.After a few years the name becomes Harrington. I'm wondering if the name may have been originally Hethrington?Her maiden name was Carr. Her mother may have been a Maguire.They are Catholic.