Will the LDS Church exist in heaven or will it be another organization?
Upon reading your question a thought enters my mind and heart, “What is The Church of Jesus Christ of Latter-day Saints”? If we go to Lds.org we can read the following quote from Joseph Fielding Smith, “We announce that The Church of Jesus Christ of Latter-day Saints is the kingdom of God on earth, the only place where men may come to learn the true doctrines of salvation and find the authority of the holy priesthood.” (Source) The Church of Jesus Christ of Latter-day Saints is the kingdom of God upon the earth. Anytime there was a patriarch or prophet teaching to the sons and daughters of God, and they met in places of worship, a church was probably established.
Let’s review some examples from scripture providing different churches established, or that are mentioned in scripture as a Church organized by God through his servants (patriarchs or prophets):
1) The church of Firstborn: “Because Jesus Christ is the Firstborn spirit child of the Father, He is the “appointed heir” (Hebrews 1:2) of all the Father has. However, He wants all of Heavenly Father’s children to share in this inheritance. We have the opportunity to be “joint-heirs with Christ” (Romans 8:17) and be numbered among “the church of the Firstborn” (D&C 93:22; see also D&C 76:51–54). Elder Bruce R. McConkie taught that “members of The Church of Jesus Christ of Latter-day Saints who so devote themselves to righteousness that they receive the higher ordinances of exaltation become members of the Church of the Firstborn” (Mormon Doctrine, 2nd ed. , 139). In this way we also can receive all that the Father has (see D&C 76:55; 84:37–38).” (Source)
2) The church of Enoch: In reference to those who receive God and his Christ (celestial glory), “These are they who have come to an innumerable company of angels, to the general assembly and church of Enoch, and of the Firstborn.” (Doctrine and Covenants 76:67), This would have been the Church organized by Enoch which is now in heaven.
3) The church of God, or the church of Christ (Book of Mormon): Alma preached in private and brought people unto Christ, and we learn this, “And they were called the church of God, or the church of Christ, from that time forward. And it came to pass that whosoever was baptized by the power and authority of God was added to his church.” (Mosiah 18:17)
An item of note, when Alma joined with Mosiah there wasn’t two churches (one established by Nephi and maintained by Mosiah, and one established by Alma). There was one Church.
4) When Christ walked the earth he established the Church: We can see reference to “churches” in different cities, “Unto the church of God which is at Corinth, to them that are sanctified in Christ Jesus, called to be saints, with all that in every place call upon the name of Jesus Christ our Lord, both theirs and ours:” (1 Corinthians 1:2)
5) The Church of Jesus Christ of Latter-day Saints: We are able to read the following, “The rise of the Church of Christ in these last days, being one thousand eight hundred and thirty years since the coming of our Lord and Savior Jesus Christ in the flesh, it being regularly organized and established agreeable to the laws of our country, by the will and commandments of God, in the fourth month, and on the sixth day of the month which is called April” (Doctrine and Covenants 20:1) Latter-day Saints was added to distinguish the restored Church from the Church established during Christ’s ministry on earth.
In every dispensation, we are able to see that when the kingdom of God was upon the earth Christ organized his Church and authorized it to record who was a member in good standing and blot out those who weren’t – and He would respect that as the heavenly record! So, “Will the LDS church exist in heaven or will it be another organization?” Yes and no. The kingdom of God will exist in heaven, and the principles, laws, rules, and policies that are truths of God’s kingdom (that exist now in the Church of Jesus Christ of Latter-day Saints) will exist in heaven.