In the letters to the churches of Revelation, it seems there are inconsistencies in the meanings of the "white garments" and being found "naked". Is it talking about salvation or unbelief?
Regarding the meaning of white garments and the other symbols used in Revelation 3, it's important to remember that we must use all the symbols together as we work to arrive at a cohesive interpretation. While it may be possible to disagree on an individual element in isolation (e.g., do white garments mean salvation or works?), when we put all the symbols together into a single interpretation, they must all align.
So, when examining the five symbols Jesus' gives to describe the people in the church of Laodicea (i.e., wretched, miserable, poor, blind, naked), we must conclude that Jesus is concerned with a believer's lack of faith, not lack of works, because these terms are never used to describe an unproductive or disobedient believer. They are only used to describe a lack of saving faith. This is all the more certain when we see all five terms used together in this way. Collectively, they are unmistakably a description of unbelief.
Furthermore, Jesus says He will "vomit" Laodicea out of his mouth at the judgment, which is eternal rejection. Such language is never used in the Bible as a description of the Judgment Seat of Christ. In fact, in every major discussion of the believer's judgment, the Bible is always careful to emphasize that a believer absent works is NEVER rejected for their lack of works (see 1 Corinthians 3:15; Hebrews 6:8, etc.). So again, Jesus' clear rejection of the Laodicea church is evidence that these people lacked saving faith.
Finally, concerning Pastor Armstrong's interpretation of the symbols of white garments and nakedness, he has interpreted them in a consistent fashion throughout his teaching.
Regarding the meaning of white garments, in Sardis soiled garments were symbols of insufficient works (Revelation 3:4), while clean and bright linen represents believers possessing good works (Revelation 19:8). Notice in both cases, the believers always possess white garments. Possessing a garment is the symbol of being "covered" in Christ's righteousness (i.,e., being saved), while the degree of cleanliness of the garment reflects the person's witness by good works. Pastor Armstrong applied this symbol consistently in his teaching saying that those with garments are saved, those without garments (i.e., naked) are not saved, and the cleanliness of the garment reflects the believer's degree of good works done in faith. When Jesus commands the church in Laodicea to obtain white garments, He was commanding them to believe in the Gospel.
Regarding nakedness, the meaning of nakedness in Revelation is always a picture of unbelief, and Pastor Armstrong always uses it this way. In Revelation 3, Laodicea is unbelieving and in Revelation 16:15, Jesus is addressing the unbelieving on earth. In that verse Jesus warns He is coming like a thief upon the world, and unless a person is saved (i.e., not naked), he will perish.