For modeling I use Sketchup Pro 8, and for the export plug Simlab 3DPDF Exporter
I have a question What kind of material you need to use the model to show the effect of gloss or matt?
Does this effect obtained by the plug or do I have to use a newer version? If so, how?
Actually SketchUp material enables you to set only one color and texture for each face.
So my advice to you is to transfer the model to SimLab Composer where you can define the values on the different color component to get the material effect you are looking for