15 years ago....
...I painted the top 6' of my mast blue. Made it real easy to spot in a crowded anchorage when you are headed back to the boat and aren't sure exactly where you left her. I just cleaned the surface with acetone and used an epoxy based paint. It has held up very well. I'm not sure about gold paint, but I'm sure any paint store could custom mix colors for you. The aluminum that I've seen that was gold colored was anodized gold.