I know u get multiplier, for example the sniper rifles have a 10x multiplier(i think) and so on. So the damage to be the same between a 300 auto and a 300 sniper is not possible, pvp for example sniper will kill in 2 shots to the upper body which is like 2 seconds(most snipers) in 2 seconds most autos will not be able to do the same dps. So i think the attack ratings are pre-multiplier. And that multiplier might be different based on legendary/exotic/special/heavy and very likely the rest of the stats of the gun