Painted Vs. Unpainted Factory Bumpers

Just got clipped by the mailman and the bumper just shed the paint.

The claim is covering the replacement so why not leave the new bumper unpainted and never worry about it again the truck is gray so it close to start with

But the Factory has 2 different part number for SR5/TRD bumpers that eventually get painted and bumpers that never get painted?
Anybody know if there's a difference?

Looked for an aftermarket steel bumper but the pickin' are slim for a 2012 except Baja types and that's not an option.

 

Unpainted bumpers

&

Chrome bumpers

TRD Offroad comes with chrome bumper.
TRD Sport comes with painted bumper.

 

I think the ones to be painted are smooth and the ones not to be painted have a little texture.