Need advice on removal of bed wood from 71

[Carl Spangler]

I'm about to replace the wood on my original 71 short step side bed. The bed strips are held down by a bunch of square nuts that are recessed in the cross rails. Do I need to get a square nut socket to remove these or is there some other trick method? In a perfect world I'd reuse this old HW to keep the truck as original as possible.

Thanks!