Old Digger - Just guessing here, but it looks like an early Archaic knife to me. I don't think it's paleo and I don't think it's a preform or unfinished piece. Obviously it's a very nice piece.
Usually and not always the bigger the knife the older the piece.
I'm always open for suggestions, due to fact that there is no way of knowing it's age. But it may be possible to estimate it's age by it's workmanship.