Shinbone / Franc, I have an XE grade CSMC fox, 20g. It has the diamond shape grip you described. It does feel good when you hold it. The grain in the stocks grip area of this gun doesn't seem to be layed out for maximum strength. Sometimes I wonder if the diamond shape was used to provide a little extra wood through that area. I really don't know why it was chosen but it does fit in the hand nicely.
terc