Interesting research there. I don't know the answer.

One piece of the puzzle to determine, if possible ---
Nevada Gaming Control (or its predecessor) has always issued gaming licenses, since 1931, but I don't think they started approving chip designs until more recently. When??**

If chip approval was necessary back in the 60's, then Moulin Rouge owners would have needed an explanation for them. If not required, then the owners could have made them for any reason.

(I can think of some less-than-honest explanations for this chip production too, but it would only be speculation.)

**The Horseshoe chips, with Binion's scratched out and B---n's replaced (for Joe W. Brown's period of operation) occurred in the mid-1950's, I think. So maybe NGCB was exercising oversight of casino chips back in this 1960's Moulin Rouge period.