With Bali and Lombok it is often very difficult to tell since Bali ruled Lombok for a bit of time. The missing "ribbons" on the sheath stem were most probably a simple rattan weave. As Jean has pointed out, the walikat style sheath is somewhat rustic and i have never see that little belt stop on the top part on a keris sheath before.
The blade is certainly antique, but i am not particularly good at pinpointed such things. Always very difficult with keris considering that styles are repeated again and again many years after the time they originally appeared. I think it would be fair to say that yours appears to be at least from the first half of the 19th century though it may indeed be older.
I would say the horse hair is more likely than human in these hilts. I have been told that this style of hilt was often employed by warriors as these hilts provide a good grip. But that might be nonsense for all i know.
