Anna:

Found it. I'm not an expert at i.d.'ing chips (sounds like Gene has already figured out the mold) or accessing manufacturer records (others have those), but I can find a fair bit of information about illegal clubs, etc... around Chicago from the newspapers.

I did not find anything on a Plantation Club or a similar named gambling place in the Chicago area. There was one near Indianapolis, IN however, that seems to have been a major operation. And you know about the Florida one, which is often claimed to have a Capone link.

Hope this helps.

John