Blake T. Ostler argues that the Book of Mormon is an ancient record with nineteenth century expansions.
Blake Ostler, "The Book of Mormon as a Modern Expansion of an Ancient Source," Dialogue: A Journal of Mormon Thought, Spring 1987, 66-123
This essay has attempted to identify and define some expansions of the Book of Mormon and to demonstrate the value of such a model as an explanation of the book. The expansion model requires coming to grips with larger issues concerning the historicity of scripture and the plausibility of revelation as a partial explanation. Evidences concerning the historicity of the Book of Mormon certainly will never be explained to the satisfaction of all, but a universally acceptable proof is not necessary to show that many of our common assumptions about scripture prevent an adequate interpretation of scriptures and their historicity.
The conclusion that the Book of Mormon is pious fraud derived from nineteenth-century influences does not logically follow from the observation that it contains KJV quotations and is expressed in terms of a nineteenth-century worldview. Nor does it follow that doctrinal developments cast doubts on whether earlier expressions reflected an authentic encounter with God. All expressions of revelation must be communicated within their author's framework of thought, a framework limited by its assumptions. Nor does it follow that if the book derives from the revelation of an ancient source it must be explained exclusively in ancient terms. Fundamentalist views of revelation and scripture that give rise to such assumptions are grossly inadequate.
The views expressed here logically preclude taking scripture as a sourcebook of axiomatic truths which can be wielded as a sword of the excluded middle to exclude all who disagree on religious issues with the true understanding. They do not, however, exclude taking seriously the possibility that God is involved in human experiences giving rise to scripture. The Book of Mormon is worthy of serious consideration and respect. It is a sufficient foundation for the community which reveres it as scripture. The refusal to engage the richness, complexity, and even the problems of the Book of Mormon will impoverish our religious lives as individuals and as a community.