I agree with Michael; some sort of quite late conqoction. May be authentic as in used by the Mentawai (in 1970's or so?), but not antique.
As I have owned a genuine antique one some time ago I hardly recognize this as being a palitai. Usually they are more reddish in color, scabbard is more straight and the projection at the handle-end had a smooth curve with -as this somewhat has- a 'ridge' in the middle. I dont recall having still pictures of it in my documents.
So you can sleep tight again Detlef; no need to remorse over this missed chance of this ebay "palitai"!