In Words of Mormon 1:3 we read Mormon’s introduction to the small plates:
And now, I speak somewhat concerning that which I have written; for after I had made an abridgment from the plates of Nephi, down to the reign of this king Benjamin, of whom Amaleki spake, I searched among the records which had been delivered into my hands, and I found these plates, which contained this small account of the prophets, from Jacob down to the reign of this king Benjamin, and also many of the words of Nephi.
If Joseph Smith created the Book of Mormon wouldn’t he naturally put this introduction before the small plates rather than after? This practice of “subscriptio” is common in Mesopotamia and other parts of the ancient world but it is unlikely that Joseph Smith would have known that.
Why would Joseph introduce the small plates after the reader has already read them?