While removing the rear axles for a swap out of the differential to a 2.47 and annular axles, I noticed the trailing arm shifted when the axle end was removed from the hub. Also, the axle end bolt and sleeve was covered with a rusty powder. My assumption is that the rear wheel bearings are shot on one side. Probably due to badly worn trailing arm bushings.
Currently, I'm waiting on the slot nut socket to arrive and I wanted to order the wheel bearing kit. However, there is a question regarding the included parts. What is the rectangular plate, with a hole in each end, used for (SKF) in this pic?
http://www.pelicanparts.com/cgi-bin/ksearch/pel_search.cgi?SUPERCAT_FLAG=Y&make=MBZ&please_wait=N&forumid=&threadid=&command=DWsearch&description=123-350-0068&I1.x=0&I1.y=0
I've searched through the FSM several times and there is no mention or picture of this rectangular plate. Is it something used on a later/earlier model?

Just not wanting to order the incorrect part. Thanks!