Here a thread where two makers of this specific hilt form, father and son, are mentioned. This one could be the work of father.
http://www.vikingsword.com/vb/showth...light=gerantim
Regarding the feature on top of the hilt, Jasper and Mas Pirngadie calls it Liking Pakoe (Paku) and describes it as a "monsterlike" figurine of an animal with tail rolled up. At that time (before 1930) they already couldn't find out the meaning of it and wrote - pepajasan, just an adornment, without symbol value. Jensen compares it with a figure called quadruped of Indra from Majapahit period.
On newer Gerantim (like this one) this feature is even more simplified, so perhaps the meaning is completely lost.
The blade... just like a Karangasem royal Keris stripped of its Kinatah
