Is 'Gracis' the correctly spelling of Agustino Gracis' last name?

Agustino Gracis is regarded in our family records as the earliest known ancestor and the root of our family tree. According to these accounts, he was a Madeiran who later traveled to British Guiana as an indentured servant. However, the surname Gracis is a rare name more commonly associated with Northern Italy, which raises several questions. Is it possible that his surname was recorded incorrectly? Could his original name have been something entirely different, or might it have been misspelled in records that were later passed down through the family?