I like to get my information first-hand since I’ve seen some impressively glaring omissions (or worse) in supposed-to-be-reliable sources. Not that I totally ignore that; I reconcile all my sources and try to make sense of it all.
I’ve been trying to get a handle on when the W126 range split. My 1984 W126 4-door is significantly different (as to a great many little things) from my 1989 W126 4-door, and I’ve been trying to find the exact cut-off when the “significantly revised” range was introduced.
At this point, my conclusions match what Wikipedia implies: the 1986 model year was the first of the revised models.