I'm looking for a replacement bed side panel support bracket and splash guard for the passenger side of my 1987 long bed (Driver's side shown.). What is the proper name and/or part number for this assembly?

I'm having no luck searching under the name I just gave.

 

I have always called them a fender brace. Not sure that is the proper name though. Inner fender shield might get you close.

 

You could easily make your own with some metal stock from the hardware store.

 

I'll bet you can find those in your local wrecking yard. I think those are low demand items and should be plenty of them waiting for you to pick n pull.

 

^^^THIS^^^

You can use this search engine to find a Bullnose truck in a salvage yard near you.

http://www.car-part.com/