There are certainly some effigies that show the back of the cuisse closed with another plate.
For example the tomb of Richard Pembridge from 1375

pics from Roel Renmans at flickr:

http://www.flickr.com/photos/roelipilami/1624.../lightbox/

http://www.flickr.com/photos/roelipilami/1624.../lightbox/


But one could argue that the "back plate" is in fact leather. There are no artikulations visible at the outer side of the cuisses, and the style in which the parts are tied together at the inner side of the cuisses does add to the impression, too.

The same is visible on the tomb of Lodewejk van Lichtervelde from 1380
(same source)

http://www.flickr.com/photos/roelipilami/2803...468647900/

http://www.flickr.com/photos/roelipilami/2802...468647900/

Interesting, that could better explain what's happening here....

http://upload.wikimedia.org/wikipedia/commons...Dragon.jpg

Whether the mail is stitched to chauses or on the back side of the cuisse.