Allan Myers had a list "Dating Chip Molds" in an old
Club newsletter. It showed the Christy and Jones mold as
beginning in 1955. (Another source says 1958.)

If you want to know the date of molds, my Mold Design Web
Project may help. For example, click here:
http://www.antiquegamblingchips.com/molddesign_manmade.htm#md77

Robt.