I finally got (from Keith Reeves) a number of this mold design (Borland's Blue Book #52; I call it #41) -- 24 flat squared chain links:

Till now I never saw one of these. I didn't know anyone who had one.

Look here:
http://www.antiquegamblingchips.com/molddesign_chain.htm#md41

I'll sell them for $8 each postpaid.
Best wishes,

Robert Eisenstadt, 140 Cadman Plaza West, # 26-C; Brooklyn NY 11201.