I think I have the most illegal chips used in the place than any other. It was a big operation.
A Hot Springs collector sent me a scan wanting me to tell him it was HS. Not! So I added it to my collection.
Only denom made with this hot stamp.

Delivered to J. Barnett Jerome Hotel, Hammond, IN
Used at:
Owl Club
Calumet City, IL

Joe Barnett was a member of the Chicago Heights (south suburban) Crew of the the Chicago Outfit. And an employee of the Owl Club, a crown jewel of a gambling place. John Binder has a check made out to the Owl Club which is endorsed on the back by Joe Barnett and several of the other employees.

John Perry started it as a little place in Calumet City. Then guys like Accardo, Ricca, Campagna and Frank LaPorte came in as his partners and it went big. The JP are his initials.

I once showed some JP stamped chips (there are multiple varieties delivered to Joe Barnett, etc...) to an old time gambler who worked at the Owl. He said "Owl Club. John Perry."