On LPTV's recent video "Special Announcment About Medal of Honor Warfighter" There is a song being played in the background with an acoustic guitar that sounds like Castle of Glass. Added to the fact that in the Behind the Scenes Videos of the Making of the Castle of Glass Video, you can see Brad playing an acoustic guitar, I think there is quite a chance that the Moh Castle of Glass is an acoustic remix.
I don't think they'd release a remix in the official video... Dunno. I think it's just for the atmosphere.
It is. They've been using various combinations of the multitrack stems from the album version in all of the MoH-related promo videos. Doesn't really mean anything in terms of the version used in the video itself.
You can actually hear the acoustic guitar in the album version too. It's not that clear in the main, but if you have the instrumental version then you can hear it at 1:12. I hope they release it. It's pretty nice. I think they will release it in Underground 12 or something like that. EDIT - Here's the link to the instrumental I was talking about http://www.youtube.com/watch?v=WLhUvguORFI&t=1m11s
Electric guitar doubled by a backwards piano loop (the piano plays the intro part by itself). There's actually an electric guitar in the preview video too, it's just not the "main" one that's most prominent on the album version. There are actually 3 guitar tracks playing through a good portion of the song.
In the preview of the music video shown on Spike, the instrumental playing during Mike's opening verse was much more ambient. It was missing the beat and subtle electric guitar (or synth?). so it looks like it might actually be a slightly different version for the single.