*Usually* special content included in Limited/Collectors editions are not made available to the rest of the population later. It's a perk for those who spend the extra money on the game. Also, pre-order bonuses specific to where you pre-order the game are also *usually* exclusive to those who pre-order. In some ways it is kind of unfair, but there has to be some sort of reward system for people who pre-order or fork over extra cash for special editions. Pre-orders tell the stores how many copies to buy and when done enough ahead of time can also give developers a good idea of how the game is going to sell. At least the weapons from the DLC and pre-orders aren't included in the achievement........