You cant reach it from the bottom as it is blocked off exactly half way between the bottom and top bolt. Only visible access i can see is from the top.
Like 2ManhyTrucks suggested, possibly the stop midway up the stake pocket got pushed down. All of mine were broken away, but not completely detached. They should have originally been spot welded about mid-height of the stake pocket where there's a thru hole.
Kevin, looking closely at your picture, it looks like the upper nut has a flange. Could it possibly be a rivet nut?
Phil, yes, that's a crimped in nut (or rivet nut). I tack welded it, because it was slightly loose. Comediann probably has the same issue. They're not really very secure, especially when the threads are rusty.
