I think our timelines differ very slightly but my take is that the 1990s 3590 Moonwatch became the 3570 in late 1996. At this point it continued with the tritium dial but gained a newer 1498/9 bracelet design and got the 1861 cosmetic movement upgrades. Around a year later, ie late 1997/early '98 the tritium dial was replaced by the SL version which continues to this day. Around this time, the 1998 bracelet (coincidentally model number and year of intro) was rolled out with its wider clasp, this ran until the screwed link version and suitcase kit were introduced around 12 years later.
This is why I say a SL dial Moonwatch can't have a 861 movement, the timeline wont allow it. The 1861 was already in use for around a year before the SL dial was in use.
I wont argue with you if you think I am out by a year or so but as I say, this is my take on it.
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