Again, many times a coin can be dated even if it has not readable date, by other attributes and the other attributes confirm it is not any variety of 1821 and than looking at the date, it is a 3 not a 2. Corrosion plays tricks! With that said, I put together photos of both 1821 varieties, your coin and what I said it is a 1831 Newcomb 3 variety. Just look at the size of the numbers of both 1821's and then your coin, than look at the spacing between numbers and your coin, then compare with the 1831.