If you could salvage these items, through the use of the /preorder command, you could basically have an unlimted amount of them to salvage, only requiring that you buy kits.
I got mine by buying the game through Gamestop. Each store had its own exclusive weapon for preordering the game, but these bonus packs, which also include a poster and a few other things, were left over after the game's realease. Thus, they're still available when you buy the game online.
