I'm not sure how KV makes his dials and of what.
Breguet today uses a disc of gold, which is the silvered and given a treatment to prevent oxidation. I believe guillochéd Pateks use this method, as a PP guillocheur told me they use a gold disc as a base (brass for practice).
A.L. Breguet originally used and JN Shapiro and others today use a silver disc, which is washed with acid several times to make a white oxidized layer. As we can see from A.L.Breguet's old pocket watches, if well cared for, this technique can last beautifully for centuries.