Absolutely; it is likely that if you are part of a church, you do too. Consider that it is the case today that most churches either call themselves by the name of Church of God or Church of Christ (such as the Mormon Church, Apostolic Churches, Assembly of God, or Mennonites) or they still hold that they are a church of Christ, including the Catholic Church, the Baptist Church, the Methodist Church, and the Presbyterian Church. Very few people who claim to be Christian deny that only those who are members of the Body of Christ are sanctified (Hebrews 10:10). Paul made it clear that any church founded by a man cannot save (I Corinthians 1:12). So most churches that are not universalist in doctrine would probably agree, only those who are with Christ are saved. So a better question is “Do you believe you are the only Church of Christ”. There can be other churches of Christ, but not as any kind of denomination, which is defined as something of another name. We believe that any church that is modeled after the first century church of Christ is Christ’s church. This can be identified and confirmed in that the Bible is the only source of doctrine (Romans 6:17, I Timothy 1:3, 6:3, II Timothy 3:16, II John 1:9), Christ is the only head (Ephesians 5:23), Elders/Bishops in each congregation are the only overseers, and only of their congregations (Titus 1:5-9), and believers are determined or saved not by men but by obedience to God’s pattern of salvation. They call themselves by no other name but the name of Christ (I Corinthians 1:13), both personally (I Peter 4:16) and as a church (Romans 16:16, I Corinthians 1:2). You can learn more here: Is There One Church?