I'm on vacation this week so I haven't been able to read around lately, but if anybody hasn't seen it, it looks like this is indeed a mistake.
http://www.gamesindustry.biz/content_page.php?aid=27372
"High Street retailer HMV has admitted a pre-order listing for Metal Gear Solid 4: Guns of the Patriots on the Xbox 360 was a mistake by its online admin team."







