Really depends on the look you are going for.
Bonding the scoop on gives you a very clean look and most people(non-Cobra enthusiasts) expect the scoop to be fully integrated as that is how scoop are on other vehicles.
I must admit I haven't seen dsus fasters used for the scoop. It's not like you will want to remove it very often. And removeability is the main advantage of dsus fasteners.
Most common are rivets and stainless button head bolts for attaching the scoop.
If it helps, I've documented some of the most common rivet patterns here:
Bonnet & Scoop Rivets
My Cobra has the 12-1-12 pattern with 3/16" rivets.
