MTV Multiplayer Blog discovered that if you have played and earned certain achievements in the previous two Gears of War titles, you may be given some special unlocks in Gears of War 3.
Additionally, more chrome skins are awarded for doing something in the PC version of Gears, or doing something in Gears 2. The details were vague about what was needed to be done though. All of these unlocks will be purely cosmetic and will not give one elite group of persons an upper hand over anybody else.
It's mostly around weapon skins in terms of tying into historical stuff. Two of the ones...I guess we haven't announced this but we have to announce it eventually, right? Two of the weapon skins are based on historical weapon skins, so if you want the gold lancer and the gold hammerburst in 'Gears 3,' you get them by owning the gold hammerburst and the gold lancer in 'Gears 2,' so those skins transfer over.
Additionally, more chrome skins are awarded for doing something in the PC version of Gears, or doing something in Gears 2. The details were vague about what was needed to be done though. All of these unlocks will be purely cosmetic and will not give one elite group of persons an upper hand over anybody else.