Dear Jhony,
I have similar feelings as Michael regarding this rencong.
The ivory handle and scabbard have a strange color.
The carving of the handle is very unusual.
That, together with the very rusty blade and the fact that it has been recenlty acquired in Aceh makes me suspicious.
As for the gayo aspect.
I am much less of a reader than Michael and Erik.
So my knowledge is limited and only based on specimins I have seen in collections and books.
But I agree, the scabbard makes one think of gayo, but the blade and handle not.