Besides BKBUNNY who was gifted FoAF, the weapon is confirmed to not be obtainable in the game as of right now. The -blam!-ing "Ooooo here's my theory on FoAF" and "it's in the game, here's a screenshot" is so old. Everyone's favorite Luke Smith confirmed it is not; aside from BKBUNNY who was gifted because he is sick and destiny helped him recover.