In a 24 June 1978 letter to the editor of the Salt Lake Tribune, Eugene Wagner wrote: “Why don’t they publish that revelation and let the Lord speak in his own words?”
In early Mormonism, revelations to the Prophet were documented so the faithful could read the words directly from the Lord. There is no written record of President Spencer W. Kimball’s 1978 revelation; reversing the priesthood ban on the black race.
The simple answer is this: How would the church leadership write a revelation from God lifting the priesthood ban, without indicting God as a racist?
Therefore, no documentation.