From what I can tell, they're cut from a single piece of wood, and are not laminated.
here's one with the view of the interior
Here is a picture showing one that's still intact along with several that broke.
Here are some close ups of the guards I would like to be fashioned out of French walnut (What a pain in the ass to find a picture that gives an idea of the thickness of these things) The first the one in question is on the far right second image it is on the bottom.