Well, it's apparently not unique. After searching the web, I finally found another example from different dies on acsearch.info: On this coin, the eagle's head is lower and there is something to the right of the eagle's head that looks like a feather...??
Hmmm...I can't get the image to copy for some reason, so here's the link: http://www.acsearch.info/search.html?id=1848655