First, thanks for all your comments, they are very interesting and instructive.
Because of the Ganja:
I added pictures of both sides. I don't think that it is carved and I can't see any remaining gold on the blade.
Concerning the hilt cup and ring:
The cup could also be a copper alloy, at one point it shines golden through the dark surface. But maybe it is silver, I'm just not sure.
I added two pictures of the ring.
Yes, David, you are right, there are real stones in the ring. It's no glass, because they have a lot inclusions. The ring itself shines golden and had no patina as I got the Keris some years ago. Because of that I suspect the material is this indonesian gold alloy, called suwasa. But maybe it is just brass.
It seems to be right that the Keris is incorrectly mounted. But the hilt stucks and I wouldn't like to damage anything.
And David, of course the wood of the sampir is far too good to cover it with silver. Maybe my question was a little misleading. And yes, the wood has a chatoyancy effect. What I meant was the angsana, but different wood is normal, as the collectors said here. So I don't have to search for a silver mounting
Best
Robin