"In most cases, if the owner of this keris had the money, a new sheath would have been commissioned. It this case it would seem they did not. "
David, this makes sense.
But the quality of the silver work is on a high level, I almost think, a new sheath would be cheaper than such a silverwork.
The upper ring was lost, I gave the sheath to a jeweller and he took ~75$ for only one silver ring.
All I can say for sure is that it is a quite old restoration because of the thick black patina, the surface of the silver is full of tiny pitting.
Roland