Well, not put too fine a point on it, but I AM a KJV scholar.
But to the point, many Christians do interpret the last few lines of Revelation as referring to the whole Bible, but that does not make it correct.
Revelation is a unique work and including in the official Bible was a cause of much contention. Centuries later, Luther alsmost did not include it in his Bible.
The KJV is a literary masterpice but a very flawed translation. It was based upon the Textus Receptus of Erasmus, which was a fairly slipshod effort to create a Greek Bible ahead of the Pope's Complutensian Polyglot. Erasmus did not have a complete Greek Revelation and created his own by translating the Latin version into Greek.