Exhaust manifold bolts

[badss98]

I have a 2007 with 34000 miles so it still has remainder of powertrain warrenty but dealer said manifold bolts are not covered, both driver and passenger rear bolt heads have broken off. Has anyone had any luck with gm to get these covered under warrenty we purchased new in march 08 but dealer says only manifold is covered if it has crack otherwise no luck Thanks mark