Is it possible to distinguish a High Relief Peace Dollar from one that isn't when it is very well worn such as this one?
All of the 1921 Peace Dollars are high relief. You can't really see the relief because it's worn away....
Agree with physics-fan. It went unsold because it is way over priced. On the subject, striking high relief coins shortens the life of the dies tremendously creating many weak strikes and few full. Which makes grading extremely difficult when attempting it yourself on a raw coin. More often than not, an MS could easily be confused as an extra-fine on these. Which is why I strongly recommend third party grading.