A couple stepside bed questions?

[67ChevyRedneck]

Finally got the rear bumper back on the truck and the fenders are almost ready for paint. I ran into a little problem when I was trying to put the rear brackets on the truck....they were hitting the back panel of the bed before the bolt holes lined up. I came to the conclusion that the bed needed to be raised. So I raised it the "redneck way" (see pics ) It looks better where it is now, since there are no body lines to match to the cab I never knew the bed was too low. How does this happen? The bed was never off the truck. I spent many hours years ago removing the crusty old bolts with a grinder. I remember there being 1/4" rubber pads, but that's it? I raised the bed about 1", the minimum to get it to clear the bumper brackets and give the tailgate room to drop without hitting the bumper. The brackets only go one way, so what gives?