I would expect that some of the beliefs unique to that "true" religion would be irrefutably demonstrably true, instead of superstitious eighteenth century claptrap.
Witnesses will sometimes tell you, for example, that they know "the true condition of the dead," but that belief is not unique to them - it is a belief shared by some other "false" religions, as well as by atheists.
WATCHTOWER, April 1, 1986, pages 30 & 31, "Questions From Readers"
(...)
"Approved association with Jehovah's Witnesses requires accepting the entire range of the true teachings of the Bible, including those Scriptural beliefs that are unique to Jehovah's Witnesses. What do such beliefs include?
That the great issue before humankind is the rightfulness of Jehovah's sovereignty, which is why he has allowed wickedness so long. (Ezekiel 25:17)
That Jesus Christ had a prehuman existence and is subordinate to his heavenly Father. (John 14:28)
That there is a "faithful and discreet slave" upon earth today 'entrusted with all of Jesus' earthly interests,' which slave is associated with the Governing Body of Jehovah's Witnesses. (Matthew 24:45-47)
That 1914 marked the end of the Gentile Times and the establishment of the Kingdom of God in the heavens, as well as the time for Christ's foretold presence. (Luke 21:7-24; Revelation 11:15-12:10)
That only 144,000 Christians will receive the heavenly reward. (Revelation 14:1, 3)
That Armageddon, referring to the battle of the great day of God the Almighty, is near. (Revelation 16:14, 16; 19:11-21)
That it will be followed by Christ's Millennial Reign, which will restore an earth-wide paradise.
That the first to enjoy it will be the present "great crowd" of Jesus' "other sheep."-John 10:16; Revelation 7:9-17; 21:3, 4.