Oh wow, so that's a over polished die too, the three legged buffalo? Interesting. Yeah it's still a stinkin lincon, I find it cool.
http://coinauctionshelp.com/filleddieminterror.html#.WSyMmIVlDYU they are right. it's rather hard to picture how it happens, but it is what it is. Over polished die
It is hard to tell the relief from your pic but I'm seeing a dent in the head. Assuming there is a dent it is either a strike through of PMD. Look at the reverse. If there is are localized scratches, scuffs, damage or a flat spot immediately opposite the dent, then it's PMD. If the defect is truly indented, then it is probably a strike through.
I believe that we have figured out already that it is an Over polished die. Look at the top of his head also, and his lips, his mouth looks open and his throat is gone Here's a few referenced images describing what to look for.