I think that stake pocket covers for the sloped bed sides would be difficult to find, but I may be wrong. If you really want to smooth the bed sides and don't ever need the pockets, using a sheet metal piece welded in place would be the way to go. But that means repainting.

Kevin
1951 Chevy 3100 work truck
Follow this saga in Project Journal
Photos
1929 Ford pickup restored from the ground up. | 1929 Ford Special Coupe (First car)
Busting rust since the mid-60's
If you're smart enough to take it apart, you darn well better be smart enough to put it back together.