When I visited with M Montoucet, he told me that it was the tempering of the metal that made the difference in tone of his triangles, and each one was different from its neighbour.
He also said that he got the material for making these instruments from a man that toured all the farmsteads in the south looking for old implements. Sadly there aint many left, and of those that are left, most end up in museums.
So the genuine t'fer is fast becoming a rarity object.
I only got mine after enquiring from many sources, and finally it was Mitch Reed who put me in touch with Don Montoucet himself.
A truly good man with a great personality and love for cajun music.
We bought three of his t'fer, one each for myself and wife, and one for a friend in England.
Most of the information regarding this instrument is in the link I posted above.
Ken