Thanks David, I can see the sense in that.
So taking the hilt separately I assume if it is from Java and if I have my history of islamic influence correct then it is probably suggests a 16C date for the hilt. Whereas if it came from Bali then it could be much later. Is it possible to determine whether this is the case from pictures? I'd imagine that styles of carving at least would be pretty regional, and perhaps the dates as in the case of the tajong. Or are these assumptions just too simplistic
What I'm also wondering is whether it is normal for a hilt to survive that long and to be attached to a newer blade. I would have imagined that the older examples came with older blades as trophies/trade items from long ago, and that a keris hilt in use was more likely to be damaged and replaced than the blade with all the blade's symbolic importance; hence old blade new hilt would be more normal. However, I suppose what you are saying is that it is most likely that both were collected separately and joined by an earlier collector.