The 1837 edition dropped the had from the relative clause “who had created them”. This may have been accidental rather than intentional; in his editing for the 1837 edition, Joseph Smith did not mark this deletion in 𝓟. There are corresponding instances of this relative clause in the simple past and the past perfect, as well as in the present perfect; here is an example of each type:
For each case, the critical text will follow the earliest reading, thus had created here in Mormon 5:2.
Summary: Restore the past perfect auxiliary had in Mormon 5:2 (“who had created them”); the 1837 loss of the had may be a typo.