According to the Watchtower Society, the appointment was made in 1919. C.T. Russell was not appointed to anything, because he died (1916) prior to Christ’s appointment. His writings were, however examined by Christ; according to the Watchtower. Knorr was not anyone of influence in 1919. The Governing Body had not yet been instituted.
So, the question is - is there any evidence that Rutherford and the board were appointed? It’s interesting that when we examine any kind of divine appointments to specific lofty positions in the Bible, we see that there were always supernatural phenomenon to make it known to other people.
This was certainly the case with Moses, Aaron, and the priesthood. (Mt. Sinai, smoke, God’s voice, clouds, lightening, etc.). Christ’s anointing was followed with God’s own voice and the dove of the Holy Spirit at his baptism. There was observable supernatural phenomenon when Christ appointed Paul.
Some kind of scriptural precedent should apply when it comes to those claiming the office of Christ's Faithful Steward and Jehovah’s channel of communication to the entire earth, should it not? What do we have with the Watchtower Society? Well . . . they told us they were. Followed up with several embarrasing false prophecies, discarded teachings, and a scrap heap of "old light".
I would say that the phenomenon (or lack thereof) speaks for itself.