there is a number of stories, one is to do with the making of a famine pot, which would tie in with the nickname cooper. That tends to be the official line, it's the easiest way to explain to people not from the area why everyone refers to me as Pott!!!
I also noticed Ballymagan being mentioned, on the other side of Falask hill is the other Pott farm where my father was born, the postal address on this is Ballynakeeloge, Ballymagan. Ballymagan was the local post office.
I will dig out some family history to see what I can find.
If you are on Facebook look up the Inishowen Heritage page, some very knowledgeable folks there.