Hi Jose, 
 
No, with my admittedly limited experience I can't be absolutely, positively certain but even if it the "back" third portion were to have been sharpened in that manner sometime after it's manufacture; it would appear it was done very long ago and indigenously, which would still make it a valid sub-type? 
 
Best, 
 
Ray
		 
		
		
		
		
		
		
		
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