It has arrived and to my surprise it is really rather nice.  I do not know what to make of it.  There is quality to it, even patina. It has been constructed with a lot of consideration to weight and balance.  It is light and although one could make a mess of somebodies head and face with it I do not think it has been made as an axe.  The stone is the right shape for stone blades from the plains { I will upload pics from reference books }  
I have taken some pictures that differ somewhat from the sellers.  I think they are quite interesting when seem in the light of this thread-
 
http://www.vikingsword.com/vb/showthread.php?t=18864
If I were an authority I might suggest that this may well be a coup stick that just happens to be in the form of an axe.
Not all coup stick are long and like a Sheppards crook { I will upload pictures }  I am not saying it is something from the times when Red Cloud sent the army packing.  The big but is when does traditional art stop and recreation for a mass tourist market  { not to mention the fantasy market, dream catcher style } take over.  I might suggest there may well have been a period of transition where real or of the right ethos art was made for limited sale around the turn of the 19/20 centuries.  Many real experienced warriors joined Buffalo Bill?  It could still be a load of c--p.