Here's the thread that gives all the info for replacing the non storage jump seat arm rest top, to the one with storage.
Skipping ahead to page 7, Jeffed's post on June 13th, you'll see the part number for the armrest. (Top seat portion) 84647286
Then on the next page, you will find the clip part number, which you need 5 each of. 11549266
Big time thanks to Jeffed for posting his results, along with the PDF document he posted on June 13th as well.
IMO, this is quiet possibly the most epic "must do" mod on Custom and Trailboss Custom's, short of the exhaust mods.
Pic that I attached is from that thread.
Hope this helps.
-Patrick-