Hello,
I bought this keris for sheath without even seeing his blade.
The warangka is in the Gabilan style with a very thick brass pendok (1mm thick minimum) with a strong hook.
The blade was a pleasant surprise because it is old and little damaged and elegant. But I think it looks more like a Central Java blade than a blade from Madura. In addition the sheath was clearly not made for this blade.
The Mendak is made of brass and is partially covered with a "brick" color paint. I have supposed that it may have been varnish if the wood of the sheath was refinished without removing the blade.
The handle is in a style that I appreciate very much, but I find that the quality of his carving is much more crude than the warangka. In addition I do not remember having already seen this type of handle associated with this type of warangka.
All these details make me think that Keris is a mix even if this mixture seems old.