Congrats again, Willem!
While the blade may well come from Aceh, all the fittings do look Karo Batak to me: IMHO a good, genuine piece. It is known that the sikin / peudeueng panjang was also used in the Batak area but examples appear to be quite rare.
Gavin offered its small brother a while ago:
http://www.swordsantiqueweapons.com/s628_full.html
(pics attached for archive purposes)
Regards,
Kai