~~~ are at least three Ameeican-style chips I know of with only a '42' on both sides and one is on the CG.

This is hand carved and the depth is that of the the casino board game bone and MOP pieces from the early-1700's prior to the hot branding iron method used in Central Europe, but most of those pieces in collections are denominated in multiples of five... so I don't know what '42' means.