Thanks, Tom. I did think the reference was to the sharp outer edge.

However, I see no difference in the two chips in the area where the plastic meets the coin inlay. The sketch below (from Wikipedia) shows a bevel and a chamfer in concept. If the inner circle of the chip has either kind of relief, it's very subtle.

I guess it's possible that the bevel is hidden when the coin is inlaid. If so, that wouldn't be of much use in trying to used that characteristic to distinguish the early casino production from later Osborne production.