Thanks all for your comments!
Ben, I think it's your turn to visit Sweden.
On the brass dots I am a bit sceptical to the "cowboy counting theory"
Willem, then we are two on the Dohong/spearblade origin as a theory...
Arjan, I think so too and that the other one is more central Borneo, maybe Kalimantan/Sarawak border? And I agree on the Dohong resemblence also on the hilt style with twin dragon heads (I haven't heard about any Janus resembling god in Borneo?).
On the mandau like scabbard mine actually originally was made for a mandau when I look inside (but the fit is perfect?).
Michael