In the 1920s "Athletic Clubs" were common, and they often had gambling.
I think a lot of chips with "AC" at the end of the monogram were
athletic clubs, just like "CC" often stands for "country club".
Searching for that I found:

Imperial Athletic Club
Dayton, OH
incorporated 8-28,1920
under Social, Benevolent and Political organizations

http://books.google.com/books?id=y5hhAAAAIAAJ&pg=PA41&lpg=PA41&dq=%22Imperial+Athletic+Club%22+history&source=web&ots=839LIGH61y&sig=rUog7-nzJtP04eoN74KN7-oudo0&hl=en&sa=X&oi=book_result&resnum=1&ct=result#PPA41,M1