I recently replaced all 4 brake assemblies with the Dexter self adjusting brakes. The cost was $10 extra per assembly, but well worth it, I am very satisfied !
I don't know how well you will be able to see through the adjusting hole, but if you can see through, you could tell if they are self adjusting by looking for the lever. Also, the "star" wheel rather than having little roundish bumps as usual (don't know how else to describe) will have what appears to be more like sawtooth cuts as the lever is designed to turn it in just one direction.
The other difference between the assemblies I took off and the self adjusting back plate is the self adjusting had two plugs in the back for the adjusting holes and the old only had one. I don't know if that is a new design or are the two plates different ???!!!
Doug