In your use of the term "PLA-M-WELL", where is that coming from? I doubt it is printed on that box and suspect that it might be on the wooden chips, right?

Take a look to this EXCELLENT reference site by Member Robert Eisenstadt on antique chips and other oder gaming items. He has a reference to PLA-M-WELL wooden chips. You will need to scroll down to item "S29". There is an example scan, as well as a brief notation about the manufacturer.

As for the box you are showing, it once contained chips made by the US Playing Card Co., which means it is probably pre-1945. I suspect that it contained chips with an anchor in the design, unless "Anchor" is a reference to a certain production line. While the chip I am showing is an "embossed" chip, I suspect that if your box had been filled with them, the box would have been marked "embossed". Seeing how the box is marked "plain" and also "assorted" I'd be willing to bet that it contained 3 different colors (hence "assorted") and they were all smooth surfaced (not embossed, nor engraved) chips.

Perhaps an email to Mr. Eisenstadt might clear up what was once in the box.

Jim