Very true, it did cross my mind. Decided to go with a bandaid fix for now. Paint is last on my Sy's rebuild list for now. I was just tired of looking at active rust everyday. It was the first thing to catch my eye, especially since the truck is slammed. Now the roof has been primered, sanded and is smooth as silk.
I need all new gaskets for the windows, front, back, doors anyway. A lot of sun damage. Figure I'll order all at once. Gotta put $$$ in the important places right now.

I'm working on a tune and getting the LS1 brake setup from Acehaag.
http://www.syty.net/forums/showthread.php?t=65552 I can't wait to post some pics.
You're right though, probably still a small amount of rust under the gasket. I'll knock it out when the entire body gets stripped down for paint in about a year. This truck is going to require a lot of prep work anyway. I don't anticipate there being much more rust or enough time for the possible remaing rust to do any damage.
It would be nice to be able to get a few kills/suckers to pay for my paint :rotf:...that woudl certainly speed completion of the project up. WHile the truck looks like a hunk of junk people tend to have a little more confidence believing they are faster and take the bait. I just blasted my buddies bimmer last week. His jaw dropped when I flew by him like he was parked. Seemed even more satisfying to me with a lousy paint job for some reason.