Thank you so much for your detailed explanation on changing the material name.
As far as your second suggestion, I'm afraid that would not work for my particular use. I'm trying to get the Cut List Extension to do the sorting for me. Here is the FAQ on Sheet Material words:
*****If one of these words is found as a portion of a material name applied to a SketchUp the component is classified as a Sheet Good. ** For a sheet goods to be recognized, the sheet word MUST be in the applied material name NOT the component name.******
The only words permissible are: sheet veneer plywood hardboard or mdf, and they must be in the material name.