So judging by the master chiefs new armour shown in this link http://halo.xbox.com/en-us/Universe/detail/mcfarlane-anniversary-s2-figures/435fe423-6210-4376-904a-970839b13686#imageNumber=1 I can make the assumption that both the halo reach armoury is back and armour detail from halo 3.
What makes me think this some of you may ask, well just look at the shoulders on him for one they look like they were just placed on a default skin like with the reaches shoulders in the armoury even if this isn’t the case I hope they make it look a little more attached to the armour. now on to the armour detail as you can see there is white stripes around his arms and lags this leads me to believe that the armour detail will be coming back to halo 4
also on a off topic statement do you think that the halo 4 release trailer could be using in game graphics like in one of halo 3 trailer http://www.youtube.com/watch?v=MsiKUmyL_hY