Hi guys, 
 
Judging from the pictures, regarding the skin used on these knifes; the squarish pieces are side/belly-pieces from some species of monitor lizard (crocodile species don't have keeled scales) . The tip of the bottom scabbard could be from a snake or monitor/lizard back piece. 
 
 
Cheers, - Thor
		 
		
		
		
		
		
		
		
	 |