This is no made up piece imo.
The more I look at it the more I intend to believe the blade could be made for this mandau (by a Tausug smith what seem to be most likely)
I still need to see a (moro) blade with such twistcore this broad as on Michaels piece which could be a good candidate to turn it in the blade on Michael's.
I've seen several kampilans with twistcore blades, but the twistcore seem to be narrower as it's the case here!
Maybe it could be made for this mandau afterall???
Very interesting and I hope a forummember could post an image of a moroblade which "could be" turned into Michael's blade.
Maurice