The e-brake I belive is drum style in the rear. There is a little bit of adjustment that can be done there, but if I remember right most of the adjustment you do form the e-brake handle itself in the car.
Sorry I don't have better info, my friend had this issue is fixed it himself, he told he it was needed adjusted.
2003 Corvette Z06 - MGW shifter, Corsa X pipe, Corsa Xtreme exhaust, Texas Speed long tubes w/o cats, PowerStop rotors/pads, Conti DWS tires, C6Z51 F&R sways, C5R headlights, tuned
04 GTO - sold