Wood bed sill plate mounting bracket question

[jcwren]

The is a picture of one of one side of the sill plate on the stepside wooden bed. The hole in it aligns with a hole in the frame, but none of the bolt kits or bolt diagrams that I can find indicate if this SHOULD be bolted to the frame or not.

If it should be, is there any bushing that goes in there? I have the pad kit for the bed rails, but there's only 10 pads, and there's 5 rails with 2 pads each.

The 2"x6"'s are in there to space the bed sides up while I get the bed wood installed. They're not actually part of some ghetto 3" bed lift kit