My 2000 had rust on the door seams (all the doors) and also the tailgate. Truck had a tad over 36000 miles. Dealer tried to tell me tough luck, the corrosion warranty didn't apply since it hadn't rusted all the way through.

I raised hell with the sales manager right in the middle of the crowded showroom floor ("Are you telling me it's acceptable for your trucks to rust within 30,000 miles?") and managed to get them to fix it at no cost to me, but it was a struggle.