In the printer’s manuscript, Oliver Cowdery initially wrote “& they both belong”, but then he corrected the text by supralinearly inserting behold. The correction was probably virtually immediate (its level of ink flow is unchanged). There would be no need to edit here since either reading— with or without the behold—is possible.
Summary: Accept in Helaman 8:28 Oliver Cowdery’s insertion of behold in 𝓟 as the reading of 𝓞, no longer extant here.