RN is correct. The Church knows Mormons are not Christians, therefore what they call “baptism” is invalid.
Even though they have an imperfect faith, the Church believes Lutherans and Presbyterians to be Christian, therefore if they are received into the Church, they are not “re-baptized” since they have had Christian baptism already.
However, rebaptism is only for pagans. I wonder if this will conclude as I suspect...