1963 Chevrolet Corvair 95 Rampside Pickup

We've had a few of these Corvair trucks up on Autoliterate. This one's at a West Coast dealer and coming up for auction very soon at B-A-T.  I always wondered what happened to the ramp on the surface that made contact with cement or loading dock or what have you. Is that a rubber fender? Factory or add-on? I like the look of the truck. Nimble.