Wow, just looked at mine, - it's 98 and I've got a little cracking going on as well. Not as bad, -YET. There's a small crack in the bend, running the length across the top. I didn't check both sides, just above the drivers door.

And I kept that thing clean since new, even the roof. At least I thought I did.

Mines white as well. Huh! Welp, rub some birds eye in there, and shellack it.

 

my 03 has it. In 05 I had it in to my painter. He said to take it to the dealer to see what they said. They said it was a manufacturer's known defect. They didn't wash the seal with the right chemical for paint to adhere to the seal (rubber stuff). They all do it.

good news! if the seal doesnt leak don't worry about it, you never see that part of the truck until you roll it over....

if you see metal, get at least some touch up on it....(el cheapo)

If it leaks, get some silicone (clear) and be done.

good luck


cheers

 

Mine look exactly like Fitz's photo.

 

My truck has it, too.
Here's a possible treatment?
Clean rain gutter thoroughly and degrease.
Tape off/cover the surrounding area.
Apply a light layer or two of clear SEM chip guard aerosol spray?
Does this stuff fade or yellow over time? (If yes, bad idea)
Just an idea.