I would think if the issue is physically the throttle body, then it should be under the drivetrain warranty.

If it is electrical, or an issue effecting the throttle body, then it may not be.

thats just from comparing it to mine and the current (2010) warranties

Chevy Warranty Information | Owners | Chevrolet

I think the throttle it self would fall under actuator. but only the "internals" are covered under the drivetrain warranty.