The 'concentric circles' description applied to coin inlay chips in TCR refers to the surface finish of the metal coin. Some chips are smooth surfaced, and some have a series of concentric circles on the top surfaces of the coins. There is a difference of opinion among collectors on this... the circles are most likely from the original machining or the polishing of the coin-dies used to make the metal inlay. Some believe these disappear with wear on the die, so that later metal inlays from the same lot would be progressively smoother. Others believe that the circles are due to a different treatment of the dies from manufacturing lot to manufacturing lot and that coins for some chip designs were always produced smooth-finished due to the careful polishing of the production dies.

I've never heard an opinion on this from someone who actually worked in chip production at Bud Jones.

The pic below is an example of the two types.