I would say the gold is more little more rare, but they generally fetch about the same. For actual hunting, I think more people prefer it without the gold. $500-700 is about right for a mint 12GA NWTF engraved. I have 3 of them all regular engraved, personally don't like the gold ones. These guns are seasonal - the price of course goes up during spring. But this year is different.. so who knows.
