The original manuscript is extant here and reads “and he went to the city Gid”. The typesetter for the 1837 edition misread went as sent (the change was not marked by Joseph Smith in 𝓟). This secondary reading continued in all subsequent editions until the 1981 LDS edition restored went to the LDS text. Later in this chapter, it is very clear that Moroni himself is there at the city of Gid with his men:
Thus went is definitely the correct reading in verse 16.
Summary: Maintain in Alma 55:16 the original reading, “and he went to the city Gid”, since verse 21 clearly shows that Moroni was there at the city of Gid.