I don't believe that this sheath was adapted for this keris because it lost its gonjo. The original opening appears to have been much larger than than. I am also not sure this isn't a complete keris with gonjo iras. If the shape of the gonjo is the same as the current open suggest i thing it is far more likely the blade is iras (all one piece). Valued old sheath are often adapted to other blades like this and this sheath has some unique pelet wood markings that were probably seen as worth saving. I would think this sheath is at least pre WWII.
Interesting hilt as well. I love the expression on this guy's face.
Unusual pamor for Bali. Lombok is another possibility. The blade also looks like it may have been shortened/reshaped at some point. The pamor seems to run off the tip.
