Leica 21mm Super-Anglon Lens Hood For Series VII Filters Very Rare

Very interesting never seen Leica lens hood for the Leica 21mm f4 Super-Angulon lenses. The lens hood offers the use of series VII filters to be mounted in the lens hood as you can see on picture no. 11 and 12 (filter is not included in the deal). The top part of the hood and be unscrewed from the bottom like it is done at the Leica 12504 and 12503 lens hoods. The series VII filter is placed in the bottom and the top part is screwed on the bottom. As said very rate lens hood. Never seen. Not sure this lens hood has ever been in production or not. Is this a prototype? Who knows?