Uncommon in most ivory sets I've ever seen; having both... which leads me to believe the slugs were mostly turned prior and the field detail later, and in this case the engraver simply pulled blanks out of stock randomly or more than one engraver was involved in producing the total quantity.

In either event, I will call most American ivory chip manufacturers a bit sloppy back then without realizing that turning the rings on both the obverse and reverse the same exact distance from the edge was a poor idea which weakens that area of the chip, especially when in play and mostly where there is a much wider rim.

This one example of wide rim has a crack in the turned ring and I've sold these in the past for far less than those which were without cracks; at $400 each compared to $600 each for the perfect examples.

I'm down to my last three examples; one without a crack and it's the narrow rim example on the left.

One note about the poor American craftsmanship... I do not see many ivory chips in the UK, India and in South Africa made as poorly...