Here is what I've been able to find at Google Books searching for "DESCOS Armurier". Too bad I don't speak French.
Histoire économique de la métallurgie de la Loire
By Louis-Joseph Gras
https://books.google.com/books?id=K4...murier&f=false
Descos aine, faricant d'armses 1829
Descos, ouvrier armurier 1890
(see photo)
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Mémorial universel: journal du Cercle des arts
https://books.google.com/books?id=D6...murier&f=false
(see photo)
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Bulletin des lois
https://books.google.com/books?id=p3...murier&f=false