I'm guessing that since they very rarely make the same chip (design, color, denomination, mold, edge spots, etc, etc.) in different inlay diameters, it would be a waste of time to have to measure every round inlay every time you listed a chip and note the size in the description. The rare times that there was more than one size, it could be noted then by a special notation.
Robert
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John Wayne at roulette table in "The New Frontier" (Republic, 1935). Not my lobby card.
http://www.antiquegamblingchips.com/lobbycard2.htm