If you're referring to the the plastic piece at the top where you step when getting in and out of your truck, I have replaced one not long ago. Mine got cracked and shot up so I ordered a replacement and swapped them out.
It's a little tough to take off. I used a plastic trim tool so I didn't damage anything and it was kind of tough. I didn't work to preserve the step since I was replacing it anyway, but I tore it up when I pulled it off. I'm sure if you took your time and worked it better than me you could take all 4 of them off without damaging anything. Just take your time and work them out of the little fastener holes. Putting them back on is extremely easy. Just snap back into place. Of one gives you trouble just give it a light tap with a rubber hammer.
