English to Spanish Art/Literary Music Accordion

In an article about accordion manufacturing in France, I came across the term "cover notes" referring to an accordion part and am unsure what it refers to. The keys/buttons of the accordion? These pieces are made in Tulle, France, I believe, and if anyone understands what this is referring to, I would appreciate your help with this term!

ORIGINAL TEXT: "Most of the pieces are crafted in France: the sculpted cover notes in the Limousin, the porcelain pieces in the Haute-Vienne, the tiny metal components in the Savoie."

TRANSLATION (tentative): La mayor parte de las piezas son fabricadas en Francia: las esculpidas florituras en Limousin, las piezas de porcelana en Haute-Vienne, las pequeñísimas partes metálicas en Savoie.