New user question about storage brackets behind rear seat

I recently purchased a 2015 double cab TRD sport.
I had test driven a 2013 DC TRD Sport a few weeks earlier, and on that one, when I looked behind the drivers' side back seat, the ball hitch and its retaining pin were secured with brackets that appeared to be removable and also appeared to be factory parts.
In the 2015 I bought, the hitch and pin were loose in the bottom of the compartment behind the seat and the brackets were missing - where can I obtain replacements for the missing brackets?

 

as far as I'm aware, there weren't any factory supplied brackets to hold the hitch and retaining pin.

someone else please correct me if I'm wrong. but I certainly don't have any brackets behind the seats to hold them. just the plastic storage panels.

 

Yeah, in my 2015 DCSB I have nothing like described. Just a half "shelf" on the passenger side. Drivers side is a full height compartment with slots to put the plastic divider blocks.