A: Partially. Presumably if someone has the weapon equipped, they like it, which would mean that the perks equipped on it are perceived to be better. At the same time, most people are probably dismantling rolls that they think are bad, so even if we could see their whole inventory, we might not catch many "dud" rolls. Overall, the phenomenon of (mostly) only being able to see equipped rolls will reduce the overall number of rolls on less popular weapons, but the perks on those that are visible will likely trend toward being more popular, otherwise people wouldn't keep the roll, let alone equip it.