Your statement is a non sequitur.
A revelation from God is true, whether or not it is written down. In fact, most of what God has done is not available for us to read in the scriptures:
And there are also many other things which Jesus did, the which, if they should be written every one, I suppose even the world itself could not contain the books that should be written. Amen. (John 21:25)
This is another apparent Changing Revelation from GOD, for many LDS members have stated that the riteS done today are not the SAME as had been done in the pAST.