Nice pedang Julien, beautiful and elegant profile.
I am not convinced it is as old as mid 18th century though, but that is always a difficult question. But the blade has particularly good edges for an origin in the mid 1700s. What have you based you age assessment on?
I agree that Buntel Mayat is an unusual choice for a pedang pamor and sees much more use on keris, though even there it is rare on truly old pieces. It has been my understanding that this pamor usually contains no core which would seem and odd choice for a sword which i would expect to be more likely employed as a weapon than the average keris. I would think a coreless blade of this length would be less effective as a weapon. But i might be off base here.
BTW, you might have noted my spelling change on this pamor and you might find this thread of interest on that subject.
http://www.vikingsword.com/vb/showth...t=Buntel+mayat