I just read Jeremy D. Smoak's new book discussing the Priestly Blessing in Num 6:24-26:
The Priestly Blessing in Inscription and Scripture: The Early History of Numbers 6:24-26 (Oxford University Press, 2015)
The book shows rather conclusively that Num 6:24-26 is pre-exilic in origin, thus showing that the Priestly source, at least in part, is pre-exilic, contra Ryan Thomas who has argued that elements of P in the Book of Mormon are anachronistic.
The Priestly Blessing in Inscription and Scripture: The Early History of Numbers 6:24-26 (Oxford University Press, 2015)
The book shows rather conclusively that Num 6:24-26 is pre-exilic in origin, thus showing that the Priestly source, at least in part, is pre-exilic, contra Ryan Thomas who has argued that elements of P in the Book of Mormon are anachronistic.