You can widen your search to any 39-48. They're the same or at least similar. Mac Van Pelt's site usually has good exploded pics of the parts.
Basically the cable enters the rear brake unit through a tube. the end of the cable has a ball on it which fits into a cup on a lever attached to the rear shoe. the lever has a reaction bar on it which transmits the effort to the front shoe.
The cable is double ended, and one end goes into each rear brake assembly. The cable loops round, and the center of it is pulled by the primary cable (fron under the dash) via an equaliser.
If your rear backplates do not have a tube, or at least a hole where the tube used to go, it may be that someone fitted front backplates on the rear.
You'll find some pics on Mac's site.
Mart.