Although I know very little about Southeastern Asian weapons, I based the origin off of shared characteristics of similar examples. Although the cross guard may be different from the one cited, the similarities in the form of the barrel hilt and the materials used show almost an identical relationship.
I compared the "four leaf" tang of this one to other Filipino knives where similar forms are present such as:
http://www.vikingsword.com/lew/w1132/w1132.html
http://www.vikingsword.com/vb/showth...ighlight=bowie
-Geoff