I saw a Cool little trunk mount that came up through the seam between the Trunk lid and the 1/4. I'm not sure how it attached underneath but no holes were drilled where you could see them.
No holes for that type of a mount. It uses small allen head screws which pinch the mount to the trunk lip. The mount has rubber on it so that the paint won't scratch. The only place that paint get's messed up is on the underside of the lip where you want the allen screws to penetrate the paint so you get a good ground.
I have seen mag mounts fall over and scratch the hell out of paint.
This is a really good antenna and mount:
[ame="http://www.youtube.com/watch?v=1mIPPf_v_Ao"]Wilson 1000 CB Antenna - Trunk Lip Mount - YouTube[/ame]