I've seen Silverstones and Daytonas where the paint has started to fail and goldy flecks show through the paint revealing the dial plate underneath. Both seem prone to it (the sort of powdery paint finish on blue Silverstones and both Daytonas could well be to blame) and it often seems to start at the middle and move outwards, so it could be moisture from the movement escaping dial-side via the centre pinion hole. Or vice versa I guess.

I've seen it on a Silverstone where the dial had become almost totally devoid of paint, but the bezel was still relatively intact. I've never seen one this far gone.