The actual Pantone color of gold is 872, well that is one of them, anyway it will come out looking like brown you can tweek the CMYK colors to get it closer though. Try C=20, M=20, Y=100 and K=0. But if you really want it to look like gold you can use your airbrush tool and hit it in several places with 100% of Yellow, and in other places with a darker brown to give the effect of gold. That effect it the way light and reflections play off of metal. Play around with that.
Tony Perkins