In the iTunes Sessions interview, 2D answered this question: "We called it Clint Eastwood because it had a kind of [something]-americano feel to the melodica line, like 'The Good, The Bad, and The Ugly', oder somefink, so we went wiff that as a theme, and also calling it Clint Eastwood had an old Reggae vibe to the name."
It may be that name because in the song, it says "I got sunshine in a bag" . Clint eastwoood, in one of his movies, he had Gold in a bag. Maybe that's why
