The VGPMX fund isn't really a fund investing in gold, silver, and other precious metals. Looking at this fund's holdings, it's many investment in companies that mine precious metals or are in the metal business. It doesn't strictly tract precious metal prices. Example there were days when gold went up, the entire stock market both here and overseas were down, and this fund tracked the stock market's movement and not the price of gold.
Second, this fund is basically closed to new investors. So it's a moot point unless you already own this fund.
I'm not trying to say this is a bad fund. Actually, I do have it in my portfolio. It's just that it's not truely tracking precious metal prices. I'm posting the funds holdings below. Also not that this fund does have pretty hefty distributions. So if possible, it's probably better to hold this in tax-exempt or tax-deferred accounts.