Those pics look just like my bed mounts, only it's the two in front of the wheel wells that are rusting through on my T. I didn't even notice it until sometime last year, which leads me to believe they are rusting from the inside out. When I noticed the paint cracking I called Toyota to see if thier corrosion coverage would take care of it, but my truck was more than six years old at the time, so no dice (big suprise!!). I tried to tell the woman that the rust had to have started long before the paint cracked, but she wouldn't budge.
Anywoo, not sure how I'm going to deal with it. I've been meaning to grind the rust away and see how bad it's gotten, but it seems like it's been raining forever here.
Anyone else have this???