If it's like the arch trim a PO added to my former 1995 Chevy Astro, it collected water at the seam and rotted the fender out like there was no tomorrow. Heck no!
But if it's a stock replacement and strikes your fancy, up to you.
1984 F150: 300 L6, AOD, RWD. EEC IV / TFI, Feedback Carter YFA Carb. Stock everything but radio (for now).