O-rings on a bolt are merely to keep gas from leaking out where it shouldn't - it's not to reduce wear between metal parts or anything (that's what a light oiling would be for). On a gun where the hammer is connected to the bolt (Tribal, Angel, blowbacks, etc.) o-rings on the bolt will also cause a little bit of drag and may cause erratic velocities if they are too tight (because drag on the bolt equals drag on the hammer, and drag on the hammer means less force applied to the valve).
I don't believe Sonic offers Tribal bolts - the only ones I know of are from DEZign (http://www.geocities.com/dezignbolts/
) - they are expensive, but they are very carefully hand-crafted on manual equipment with superb quality - Rob is an excellent craftsman.