I think the brown dials are caused by storage in the dark.
I love the fact that nobody seems able to give a definite answer on this particular issue. You've all seen plenty of close pictures of this watch in the last year or so,
馃槦 and this thread is about William's beautiful Chocolate Speedmaster,
馃グ so I shall restrain myself for this contribution and (in response to earlier questions from
@bags1971 and
@gemini4 ) focus on the question of transition from black to brown over a life time of 50+ years.
馃憥
My Dad's 105.012-65 was black in almost every picture I have of him wearing it during his life.
From the late1960's until he died in 2003, he wore the watch out and about in London, UK
I put it in a specs case, in a dark, cupboard in 2003 and hardly brought it outside until 2016.
Sadly, I don't have any old photographs of my Dad showing his watch in close up, but even from a distance the colour change of 50 years is unmistakable. How did it change from black to brown? I have no idea but here is the time line:
Between 1967 & 2003 the watch was worn out in sunlight. Between 2003 & 2016 the watch was stored in dark cupboards.