Xbox 360 question

I bought the Modern Warfare 2 xbox 360 and I was curious if anyone thinks that Microsoft uses older 360’s and just puts different cases on them and sells them as brand new? I mean on my 360 I have MLB, Gears of War and some other Gamer Icons that I never purchased or downloaded and there are a ton of trial arcade games on it also. Just wondering if everyone else’s 360 came with those. I hope they wouldn’t do that with 360’s that were sent back to them and they fixed them.