You will likely get more money on Ebay, but you also will be undertaking a humongous risk. I wouldn't dare it myself.

$20,000 is way above what any 1 BTC coin will fetch here. Premiums have collapsed and they're often no more than what you'd get for peeling the coin and selling the shitforks on it.

Just to be certain, is this a brass coin or a silver coin with gold highlights? The latter will fetch more but still not what you're looking for.