It sure dose look like someone creased them in to clear when the bed raises as you suspect.
Or someone dumpped the bed with the aprons still attached. The bed raised then snapped that attaching point off. Maybe not since the bed is sitting higher
My interior was rattle can resto. I didnt fully restore my truck, just kinda fixed her up a bit. I remember when I first joined the forum I would spend hours looking at stovebolt members build pics. Never to many pics.
Hopefully your find someone with a similar dump bed to compare the rear fender to running board area.
Thanks and Good Luck
