Yes, Nieuwenhuis. I did not check it and was confussing it with the other hilt with the bead winding in Quer durch Borneo.
Wow
you actually bought this quality handle.
It must be from the same age as Nieuwenhuis'example. Great buy !!!
As for the discussion , decoration or repair.
Nieuwenhuis' books show almost nothing but complete examples and sometimes object were even specially made for him.
So considering that a similar exemaple is pictured in Quer durch Borneo , I would surely say it is decoration.
Good luck with the customs.
Do they know it is antler (and not some ivory)
Best regards,
Willem