Hi Roger -- It looks like a "die adjustment error." These are explained on our page, here:
Looking at our page, I think the approximate values given need to be revised downward by a factor of 2 or more. Keeping these pages up to date is a challenge ...
Be careful not to clean your coin. Cleaning ruins value.
Go to eBay and search for coins with "adjustment" in the title. You will see several examples.
Hi Roger -- Wow. $2500 seems way off to me. You are correct about 'list' price and 'sold' price -- 'sold' is the only real indicator of value.
All adjustment strikes are test strikes. Mint workers are adjusting the minting machines during initial testing. The eBayer is hyping his coin by describing it multiple ways which, by the way, is a good idea when selling on eBay.
Yes, you can consider submitting your coin for evaluation. The fees involved may cancel out any possible future profit, but you will have an interesting collector piece. If you sell, and if you find the right collector, you might turn a profit.
I would submit your coin for 'conserving' as well. Conserving is a fancy name for cleaning. Cleaning coins is always a bad idea for amateurs, but professional conservers do that for museums and the like, and they are considered OKAY in the numismatic world. See this page: