In my experience this would be a Sulu blade.  The top of the scabbard in this boat shape is also indicative of Sulu pieces. 
 
However, there was a lot of trade in the region with Tausug people, so would not be surprised if it might have been traded in Sumatra.  I think it more likely that the dealer gave it a mistaken attribution.
		 
		
		
		
		
		
		
		
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