I've received a few emails over the past year taking me to task for using gold paint on bronze metalwork, especially on the bronze helmets of my Roman legionaries and the bronze gun barrels on my Napoleonic artillery.
I'm no expert on ancient metallurgy, but I can do a google search as well as the next man. A quick search for "polished bronze helmet" brought up this reproduction Roman helmet:
The image is from a German site that sells reproduction metal bits from Caesar's time. That color looks pretty golden to me. Just as a modern soldier spends time each day cleaning and oiling his weapon, I figure that any legionary worth his salt would keep his metal gear polished and oiled.
And here is a replica British cannon from the Napoleonic Wars. This is a half sized replica sold by a company in Argentina. Again, this polished bronze looks pretty gold in hue to me.