Hi Caedo. This piece looks rather contemporary to me and i could be wrong, but it appears that it has no core. It if very possibly Madura work. Others my know better.
The words "hulu", "ukiran" and "deder" all mean hilt. I am not certain if one is any more appropriate to another, though the exact culture where the keris originates might be a guide. However, as a Western collector i don't see any difference in using any of them as a descriptor and really thing the word "hilt" is just as acceptable a term to use on an English based forum.