It would seem that by and large it it not. But there is one church out there that is claiming that the Gospel is exclusively about the Kingdom of God, and NOT about faith in Christ and His finished work of redemption. THIS IS FALSE TEACHING. But this church is promoting Herbert W. Armstrong as the only man who preached the true Gospel: “And this gospel of the kingdom shall be preached in all the world for a witness unto all nations; and then shall the end [of this age] come” (Matthew 24:14). Only one man fulfilled this prophecy in this end-time: Herbert W. Armstrong. He died in 1986. No other religious figure on this globe has preached the true gospel worldwide. As a matter of fact Armstrong was a very subtle and very powerful false teacher, who influenced many. And here is his "gospel": "The gospel is the good news of the coming Kingdom of God and the all-powerful God family which will rule the earth. It includes the details of salvation and of how one can be born into that glorious Kingdom. How inspiring!" Yes, it is inspiring but it won't save you from Hell.
First of all Christians need to understand that the Gospel is the ultimate Good News from God, and has many designations, but it is still ONLY ONE GOSPEL -- "the everlasting Gospel". It is God who get's to decide what it should be called, depending on the context. When Christ preached, it was "the Gospel of the Kingdom" because it was the King who was preaching it, and directing men to see and enter into the Kingdom of God through the New Birth. See John chapter 3. But Mark calls his Gospel "the beginning of the Gospel of Jesus Christ" since the entire focus is on Christ Himself. Paul calls it "the Gospel of the Grace of God" because the very foundation of the Gospel is the grace, mercy, and loving kindness of God. He also calls it "the Gospel of God" because God is the ultimate source of the Gospel. It was designed by God and implemented by God through the Lord Jesus Christ. That is also why it is "the Gospel of His Son". And since He is Christ ("the Anointed One") it is also "the Gospel of Christ". And because Christ made peace between mankind and God at the cross, it is called "the Gospel of Peace" (hence peace and goodwill towards men).
So we come to the heart of the matter, "the Gospel of Your Salvation". No person can be saved without believing the full and true Gospel. How that Christ died for our since according to the Scriptures, and rose again for our justification according to the Scriptures. So that we might have the gift of eternal life and the gift of the Holy Spirit. These are God's free gifts of grace to the one who repents and believes on the Lord Jesus Christ.
And this is where many stumble. Why would God give undeserving sinners these precious gifts? And the answer is found in the heart of God. See John chapter 3.
1 There was a man of the Pharisees, named Nicodemus, a ruler of the Jews:
2 The same came to Jesus by night, and said unto him, Rabbi, we know that thou art a teacher come from God: for no man can do these miracles that thou doest, except God be with him.
3 Jesus answered and said unto him, Verily, verily, I say unto thee, Except a man be born again, he cannot see the kingdom of God.
4 Nicodemus saith unto him, How can a man be born when he is old? can he enter the second time into his mother's womb, and be born?
5 Jesus answered, Verily, verily, I say unto thee, Except a man be born of water and of the Spirit, he cannot enter into the kingdom of God. [Note: "water" = Word of God = Gospel]
6 That which is born of the flesh is flesh; and that which is born of the Spirit is spirit.
7 Marvel not that I said unto thee, Ye must be born again.
8 The wind bloweth where it listeth, and thou hearest the sound thereof, but canst not tell whence it cometh, and whither it goeth: so is every one that is born of the Spirit.
9 Nicodemus answered and said unto him, How can these things be?
10 Jesus answered and said unto him, Art thou a master [teacher] of Israel, and knowest not these things?
11 Verily, verily, I say unto thee, We speak that we do know, and testify that we have seen; and ye receive not our witness.
12 If I have told you earthly things, and ye believe not, how shall ye believe, if I tell you of heavenly things?
13 And no man hath ascended up to heaven, but he that came down from heaven, even the Son of man which is in heaven.
14 And as Moses lifted up the serpent in the wilderness, even so must the Son of man be lifted up:
15 That whosoever believeth in him should not perish, but have eternal life.
16 For God so loved the world, that he gave his only begotten Son, that whosoever believeth in him should not perish, but have everlasting life.
17 For God sent not his Son into the world to condemn the world; but that the world through him might be saved.
18 He that believeth on him is not condemned: but he that believeth not is condemned already, because he hath not believed in the name of the only begotten Son of God.
19 And this is the condemnation, that light is come into the world, and men loved darkness rather than light, because their deeds were evil.
20 For every one that doeth evil hateth the light, neither cometh to the light, lest his deeds should be reproved.
21 But he that doeth truth cometh to the light, that his deeds may be made manifest, that they are wrought in God.