Though I can't pinpoint (exactly) when the chip was used, I can tell you that it wasn't documented in Day's original article, but was in the addendum (1988).

I do remember Monsieur Victor GADOURY (lived in MONACO; sold chips) telling me it was in play in 1980.

BTW, Day's complete article of Monte-Carlo chips (from "The Numistmatist") is found in our club magazine.

JB