Do the codes for Space Marine only work if you pre order them?

I preordered Space Marine (xbox) at Gamestop yesterday and they told me it would come with a code for Space Wolves and Black Templars bonus armor. But I learned that that is you preorder at other stores, the bonus content is different (Bestbuy gives you Iron Warriors and Emperor's Children armor) Since this is the same company that made Darksiders I have this theory about the codes: When I preordered Darksiders, it came with a code to unlock the scythe. But all the code had you do was go in game and type in a cheat and it worked. However it was just a keyword so all someone had to do was go online and look up the code and type it in, so you didnt even need to preorder it. So is it necisarry to preorder the game or when it comes out will you jsut have to type in the codes in order for them to work? (I want to play with the Black Templars and Iron Warriors and both come in seperate preorder packs)Do the codes for Space Marine only work if you pre order them?
you would technically have to pre-order the game from both stores to get both codes. Because the only way to get the code for the game is to pre-order it. I pre-ordered at Gamestop because i love the Black Templars. The codes are only for promotional purposes and wont be available after the game is released on september 6th