at them. The one that appears light has definate circular rings on the insert, which seems to me, would be evidence of spinning, and also has a much sharper impression in the insert. The darker one has a smooth surface on the insert, except for some random scratching from handling, and the impression seems less distinct.

Hmmmmm. I can't seem to help learning something every day on the ChipBoard, even without intent. It's sometimes difficult to know what it is that you don't know.