Ken's assumptions are all correct.
I have ordered a different kit from a local MB shop that has the center bolt (my kit did not have that center bolt?). I have also ordered a new pair of brackets, one for the right and the other left. I could go through a process of drilling the head off the old bolt but for 15 bucks each what the heck...they are kind of rusty anyway.
This is one of those simple looking processes taking several days, the love we have for this kind of stuff!
Thanks for the feedback!