Oh, just noticed, you`re the hilarious person from https://www.cointalk.com/threads/collection-to-know-opinion-worth.279956/ It seems I made a mistake, this 1840CC Seated Liberty Dollar is definitely authentic, in my opinion value should be around 4,000,000 USD because Carson City Mint did not produce these dollars before 1870. For the right buyer, after slabbing, possibly up to 8,000,000 USD. Amazing, unique and totally authentic coin, congrats!
You may want to try and buy a reference book on counterfeit coins, such as this ==> https://www.amazon.com/Detecting-Co...=1466523383&sr=8-4&keywords=counterfeit+coins before investing more into purchases in India and other places.
Well, if it helps, the date on the coin is from thirty years before the mint it was supposedly struck at even existed, and the reverse design wasn't used until 1866.