I don't think this is the case here.
I know some vintage Constellations had 18K gold dials struck with highly polished dies, similar to proof struck coins.
No polishing involved there.
Mirror dials were a novel design theme in the 1950s for some vendors. My understanding is that these dials were chrome plated. Here's a Tissot circa 1958 with a polished dial:
Mirror dials were a novel design theme in the 1950s for some vendors. My understanding is that these dials were chrome plated. Here's a Tissot circa 1958 with a polished dial:
mine however has more of a gold color. I may remove the movement from the case and take a closer look at the dial.
Thin layers of different substances (such as "electropainted" lacquer) can be added on top of a reflective surface to provide different tints. The coloring process is known as electrophoretic deposition (EPD), electrocoating, or e-coating.
If the dial is polished stainless steel, I believe there are processes known as interference coloring (also called INCO coloring) that can add tints to the surface. The colors are created by the interference between light reflected off the surface and the thin transparent oxide that has been applied to the surface.