It is a teaser trailer. Tease is in the name. It's meant to taunt you, get you excited about it, ask questions. It's raising publicity. By adding the new armor, that's exactly what it's doing. There are several ways you can go from how he got it. Woken up before the actual trailer, maybe the trailer is even half way through the campaign for all we know! He could get the armor at the beginning of the game. Frankie will explain when the time comes.