Hello Roy,
Nice examples !
My feeling about the one with the brass collar is also sumatra.
I have spears with similar decorations in the wood, but the decoration continuing in the brass collar is very nice. never seen that before.
For the one with the silver collar I am not sure.
You see these silver collars also on Borneo, where it is not indigenous BTW but is an influence from abroad.
Maybe keris connaiseurs can give some clues based on the forging of the blade with the holes
It would be nice to see pictures of the other spearheads too, although they are not that elaborate, Interesting to compare them.
Best regards,
Willem