I've got plenty of coins with the Seated Liberty Design (half dimes, dimes, quarters, halves, dollars) and the one thing they all seem to have in common is the expression on Liberty's face that ranges from a frown to a scowl. Here's an example of what I'm talking about with my 1843
Seated Liberty dollar:

The one exception, however, is my 1875
Seated Liberty quarter:

Here, she has a truly beautiful smile that reminds me of the one on the Mona Lisa. I'm assuming this coin is not a fake, but it just seems odd that she has such a nice smile here but not on all the other examples I have.
Does anybody else have an example of a smiling Seated Liberty? Is there something special about this one, or is perhaps maybe all my other examples just look like they are frowning due to wear?