Cruising through the 1887 WT i came accross this that i found of interest that as far back as 1887 the Wt was sanctioning the act of disfellowshipping. Whether it included the practice of full blown shunning at that time is not eveident in the pages i have looked through yet.
Watchtower 1887 page 954 ''Discipline in the church''
Such is part of the painful duty of the present hour. Some
who once walked with us in the light of truth, clothed in the
righteousness of Christ imputed to-them “through faith in his
blood ''have since taken off that robe and appeared in their
own filthy rags, boldly inviting others to do likewise. While
it is the duty of the stronger members of the body of
the Christ to protect the weaker, in every way possible
against these baneful influences it is their duty to bind the
offenders and cast them out-in other words, to disfellowship
them-to show up their true standing, and thus bind them
hand and foot by putting others on their guard, thus restraining
their influence upon the church. Sooner or later they
will either put on the robe or withdraw from the light which
reveals the filthy rags of their own righteousness.
Mrs C.T.R