Look at the Tweet (X? Blurp? What do we call them now?) - it's got the spectrum of the panel, comparing previous and newer panels.

If you know what you're looking for in those, you can identify a lot of different phosphor configurations just by the particular shape of the RGB peaks - the older ones have a distinctive multi-peaked red emission that I've seen in various LED bulbs as well over the years.

I doubt Apple mentioned it to anyone. Applying a spectrometer to any new light emitting device is just the sort of thing some people enjoy doing.