Agree it looks like the anchor plate is missing.
It also looks like two secondary shoes. Primary shoe usually has shorter lining (and originals sometimes a different material). Primary shoe grabs and forces the secondary to engage harder by puxhing on the bottom.
So that's a possibility.

Some illustrations of original spring hookup starting '69 is here:
http://www.imperialclub.org/Repair/Lit/Master/260/Page07.htm
and of course the service manual.

Note the self-adjuster overload springs face outward. At least for '69 - ? Don't think that would cause your problem, but it must effect something or they wouldn't have made a service bulletin...
Detail in the '69 TSB
http://www.hamtramck-historical.com/images/TSBs/1969/D69-5-5%20page_2.jpg

Here's a picture of '69 10"x1.75 rear shoes etc. on my car.
Your springs etc will be a little different...