Rear spoiler rattle

[mmuresan77]

Have a '07 Equinox LS and noticed a rattle over bumps and when closing the rear hatch. After examining i noticed that I was missing one of the bolts and the other was loose that attach the spoiler to the rear hatch/tailgate. Is it a common problem for these to loosen? The main problem is I want to replace both but one of the bolts is stripped and just spins once halfway unscrewed. Does anyone know the size of this
bolt and the best way to remove what seems to be a stripped bolt? Not sure if it is the bolt or the part of the spoiler it screws into. Look forward to hearing from anyone who can assist.

[prheaume]

If I remember well it is M8x1.5 ... lost one also but was fortunate enough to find it stucked behind the tailgate lift shock. I've put some locktite before installing it back in place. There are 4 of them, 1 one each side of the spoiler and two are hiddens under a plastic cap on the tailgate frame.