I tend to agree with Gene. On a bunch of different chips of this approximate vintage, there are two "different" chips which are identical except for a similar color "variation." Sometimes when there are two clear color variations listed in TCR (maybe a beige and gray or beige and cream)there is also spotty third colored that appears just like the image on the left of your scan, making me think it's just splotchy dirty. There is a Flamingo Hilton listed in two such colors but I have one that looks like neither color and, again, looks just like the scan of the one on the left. Just my two cents worth after having wondered about it a little.

Cinch