Seriously kid. You're connecting the most insignificant things and making them look important.
Bungie explicitly stated at E3 that FoaF was not in the game at this time.
Also, in a pre-release ViDoc, Bungie mentioned unique weapons "like Fate of all Fools". Implying that it was exotic. Plus, the Stranger's Rifle looks exactly like FoaF because it's just reskin for now.