The Gold/Silver/Bronze/One Community cards that i'm talking about don't have codes at all. From what i can tell and what Troy just said they can't be loaded into the online version (when you physically get them out of packets) and are only used if you are playing the game in the school yard.
Yes you can win/unlock some online but i'm talking about the ones you get out of packets. Obviously you can't add them to your "virtual" card album when you actually own them, you have to wait until you win/unlock them.