The best explanation I've seen for the general question on "concentric circles" on any CIC chip was posted on this bb a year or two ago. The poster said a Bud Jones employee (or maybe it was Jones himself) said that later production of these coin centers used a polishing process to remove scratches on the coins that were left from the coining process. I believe it was a "tumbling" process using an abrasive in a drum with the coins. That could also explain why some later chips have faint circular scratches rather than none; the tumbling process wasn't run long enough on the batch.

I don't have any of the Park Tahoe high-denom CIC's to look at so I don't know how to answer that question.