... "Day's 5a" (Vol 14, #4 CCTN), and the inlay is known as "metal filigreed overlay" as noted in "Casino Tokens of Monte-Carlo" by Thomas C. Day.

Notice how your inlay is not fully embedded in the jeton (not being flush with the surface of the piece) as is a true "metal die-cut inlay" such as seen on the jeton below.

JB