Hallo Ben ,
IMHO this is a Javanese blade that you have there.
how is the fitting of the blade in the waranka mouth ?
It happens more to see Javanese blades in a bugis sheath , maybe it is already a long time like this , because maybe a Javanese moved to Sumatra and had his ''pusaka'' blade dressed in a ''local'' dress ??
It is just a idea , i dont know
regards ,
Danny