As discussed under Mosiah 24:13, the original Book of Mormon text has nine examples of “this my people”, including here in Mosiah 29:32. The 1858 Wright edition accidentally skipped the my in this passage. The 1874 RLDS edition restored the my, probably by reference to the 1840 edition.
Summary: Maintain the original occurrence of “this my people” in Mosiah 29:32.