Do you have ideas for how to test it and find out definitively in person? I haven't found a way to confirm one way or another.

The Graphics/Displays page in System Information unfortunately says nothing about colors, only resolution (https://github.com/shurcooL/home/assets/1924134/af4b19a3-b85...).

When looking at a 16-bit PNG of a white to black gradient, I'm not able to visually spot any banding even when zooming in. It's fairly easy to spot steps when looking at a 8-bit PNG version of the same gradient. But the same happens on the built-in display despite it supposedly having only 8-bit color ("support for millions of colors").