come without totally losing my mind over this puzzle. It's a Trick or Treat question, right? The Oil Historians at this point concur it should be the logo of the old Cities Service Company but no one has found an offer of poker chips from that firm so as to confirm it. Various oil companies have offered poker chips in the past, however. It might have been a premium awarded for a fill-up at a newly-opened Cities Service station in 1963. Cities Service as such existed until 1965 or so, when the brand name was phased out in favor of Citgo (new trademark, a triangle divided into three differently-shaded triangles to give it a 3-D effect).