Here we have an 1837 typo that has been very difficult to remove from the text, even though it is clearly wrong and virtually nonsensical. This typo was copied into both the 1840 and 1841 editions. The 1849 LDS edition (edited by Orson Pratt) restored the correct now, probably as a result of simply realizing that own was a typo for now. Pratt did not have to refer to a copy of the 1830 edition to restore the original reading, although he may have. The first printing of the 1852 LDS edition had now (since its copytext was the 1849 edition), but incredibly the second printing restored the impossible own (by reference to the 1840 edition). Pratt restored the correct now a second time to the LDS text when he did the editing for the 1879 LDS edition. The correct now was finally restored to the RLDS text in 1908.
Summary: Maintain the original now in “but now that they may foresee that he will come”; despite the fact that the 1837 typo own is impossible, this reading was retained in the text for many 19thcentury editions.