I noticed the other day that the paint on the bottom of my tire carrier was bubbling up...a closer inspection revealed that I had four/five spots were the paint was coming off due to surface rust.
The rusting areas appeared around was seems to be drain holes...however all but one of my drain holes were plugged with these...
I popped all the plugs out, gave the unit a good sanding and hit the whole thing with spray-on bed liner...it's all good now, but I thought I'd throw this out there so others can check their rear. There's nothing worse that a dirty hole on a bum.