GREEN chip (SQUARE IN CIRCLE): approx. 1948-1970s

YELLOW chip (MASON HUB): approx. 1928-1956

BLACK chip: I cannot see the mold.

Listed somewhere in one of the more recent issues of Casino Chip & Token News is a listing of molds and dates. I'm working off of my photocopy of that list at this time. Sorry for not being able to quote which issue. John Benedict