Does it count if we twist the meaning of "gold" around a bit?
Back in 2007, I was living in the area of Florida where all of the missing edge lettering George Washington "gold" dollars were being found. I decided it couldn't hurt to look for some, so I picked up a fair number of those pseudo-Mint wrapped rolls.
I didn't find any that were missing the edge lettering, but I found something much, much, better: a coin that was missing one of its clad layers. I could tell that something was off about it as soon as it fell out of the roll, as it made a completely different sound than the rest of the coins.
I bounced back and forth between different coin dealers for a while, trying to get an opinion on the coin (one, a supposed error coin expert, told me that it was worthless, and to spend it!).
I didn't have any luck locally, so I decided to try the Internet. I contacted a prominent error coin dealer, and ultimately sold the coin for a tidy sum of money- close to the price an ounce of gold was at the time.
So, from a certain point of view, would this count?

It was a Mint-branded "gold dollar" I found, and its final value was well above that of the actual gold coin most roughly equivalent to it as based on size and weight (the pre-1933 $10 eagle).
Heck, I seriously considered buying a St. Gaudens $20 coin with the proceeds from the sale, but couldn't find a coin dealer I trusted enough to make that kind of purchase.