Robin: nothing in it to say he wasn't a Native American; the only other possible positive pointers:
Before I turned, the spirit had left him
And gone to its Giver Gone to it's giver? not Christian terminology!
And give a wild whoop as you carry me along,

Take me to the green valley and lay the sod o'er me no coffin, either a pauper's burial, or a return to the land. In a later verse it mentions the graveyard rather than the 'green valley', but still no coffin.

Nigel