This is the 'Reward 1' tier for those slapping down their cash right now for the RTS sequel. 'Reward 2' will net everyone pre-purchasing a copy of Dawn of War 2: Retribution. There's a lot of '2' going on.
If things go even better then 'Reward 3' will unlock the 'Commissar Chest' which includes in-game currency for future DLC purchases and other goodies.
The pre0purchase rewards scheme has been running for a little while now for various new titles through Steam and it's obviously having some affect for Valve and the game developers to be still using it. The base offer for pre-purchase is two tank vehicle patterns; the German Rotbraun and Russian Leningrad. You also get "guaranteed beta access".
For more info on the pre-purchase bonuses check out the. Company of Heroes 2 releases in 2013.