I had never noticed it before but it seems that the gloss of Rhino custom material does not show on raytrace. Is this true?
How to achieve a similar effect?
Cycles doesn’t do different color gloss, and won’t until in the future we have capability for users to fully create shaders with all the supported nodes from right within the Rhino UI (not counting GhShaderNodes, which I haven’t looked at in a long time). At that point you could create a material that has several layers to simulate gloss.
In v7 you are best off sticking to the PBR materials (Physically Based and its simple UI variants Emission, Gem, Glass, Metal, Paint, Plastic).