I've got it(twice) but I cant get the FWC sniper(The Chosen), my Warlock uses it rarely - the low impact coupled with 6 bursts per clip makes it kind of meh, prefer 3 little words. I've got 1 char in each faction, always rolled good with New Monarchy, has all of their weapons early but can't roll chosen and I think 3 Dead Orbit guns(sniper,fusion,rocket launcher). I doubt any of the 'hidden' faction weapons are more or less rare, it's just the luck of the roll.