This reference to Gazelem is confusing. If he is a prophet, contemporary to the early Nephites, who was given a Urim and Thummim, then there must have been two sets of interpreters among them. The other set of interpreters were the ones given to the Brother of Jared. They were later buried with the plates and used to translate the Book of Mormon (See Ether 3:23; DC 17:1). Another possibility is that Gazelem is not a proper name but a title for a seer. Thirdly, the name may be a reference to Joseph Smith, who was referred to in the D&C as Gazelam when code names were used to conceal the identity of those referred to in the revelations. The following quotes are helpful.
“The word Gazelem appears to have its roots in Gaz - a stone and Aleim, a name of God as a revelator or interposer in the affairs of men. If this suggestion be correct, its roots admirably agree with its apparent meaning-a seer.” (George Reynolds, A Dictionary of the Book of Mormon, p. 92)
“This may well be a play on words. Is Gazelem the seer stone or the servant? It is difficult to tell from the passage and depends very much on the placement of a comma in the sentence. Perhaps it could refer to both. It is interesting to note that when Jesus called Simon Peter to the ministry he said: ’Thou art Simon the son of Jona: thou shalt be called Cephas, which is, by interpretation, a seer, or a stone’ (JST, John 1:42). Though this name or title of Gazelem may be used in regard to any seer who utilizes seer stones, it seems in this instance to be a direct reference to Joseph Smith the Prophet.” (McConkie and Millet, Doctrinal Commentary on the Book of Mormon, vol. 3, p. 278)
Bruce R. McConkie
"Strange and unusual names were placed by the Prophet in some of the early revelations so that the individuals whom the Lord was then addressing would not be known to the world. The purpose for keeping these identities secret from their enemies having long since passed, the true names are now found in the Doctrine and Covenants.
"Two of the names which identified the Prophet himself were Gazelam and Enoch. (D. & C. 78:9; 82:11; 104:26, 43, 45, 46.) Presumptively these and other names used at the same time have particular meanings, which are not now known to us.
“With reference to the name Gazelam, it is interesting to note that Alma in directing Helaman to preserve both the Urim and Thummim and the plates containing the Book of Ether, says that such record will be brought to light by the Lord’s servant Gazelem, who will use ‘a stone’ in his translation work. (Alma 37:21-23.) It may be that Gazelem is a variant spelling of Gazelam and that Alma’s reference is to the Prophet Joseph Smith who did in fact bring forth part at least of the Ether record. Or it could be that the name Gazelem (Gazelam) is a title having to do with power to translate ancient records and that Alma’s reference was to some Nephite prophet who brought the Book of Ether to light in the golden era of Nephite history.” (Mormon Doctrine, p. 307-8)