I might be playing fast and lose with the word "interesting", but here goes. Chip 1 (in all 3 pictures) is an original order Borland Silver Slipper $25 chip with 9/16 inch inserts. Chip 2 (in all 3 pictures) is a re-order Borland Silver Slipper $25 chip with 1/2 inch inserts.
Look at picture one. The inserts look like they are the same size, don't they? Look at picture two. Here you can see the difference in size between other inserts on the same chips. Finally, picture 3 shows a front view of both chips. The insert shown at the bottom of chip 1 in picture 3 is the same insert shown in chip 1 in picture 1. This insert is a little bit undersized. It looks to me as if when these chips were manufactured, the manufacturer was playing a little fast and lose with the measurement of 9/16 inch or 1/2 inch! The insert size does vary, at least a little bit.

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