Drip rail HEELLLPPP! Please.

[Airborne70GMC]

I have a 70 GMC short step bed that I have had for 23 years now I got the truck in pretty good shape, for a farm truck. I have found some rust on the underside of the corners of the drip rail. I plan to fix up the truck, not show just real nice. The original six has long been gone I have a correct 70 V-8 block for this truck that I ran for about 3 years with the factory Tree shifter. I have done some body work in the past, but never a drip rail. I am not sure how to approach this. Is there replacement metal for this or would a person need to make it or scavage a rail from the salvage yard? I plan to do most of the work myself for several reasons. Any help would be muchly appreciated. Thanks in advance folks. good night and God Bless you and America