That's really a Chapter that one must pay very, very close attention to...
In 1 Corinthians 15:37, Paul revealed by analogy that body which is sown (i.e. ,flesh), is NOT that body that shall be ("spiritual body"). So even right there Paul made a clear distinction between the two different type dimensions of existence and their two different body types.
And when Paul was making distinctions about different flesh bodies, he was speaking only... of this earthly material dimension type bodies, like the bodies of different animals, birds, fish. Likewise with the idea of celestial and terrestrial bodies, both are still about earthly dimension bodies of our earthly dimension (planets, sun, stars).
At 1 Corinthians 15:42 Paul begins talking about the body of that other dimension of existence, the Heavenly dimension. And he points out that "It" is sown in corruption, and that "It" is raised in corruption. I'm not sure if the KJV translators understood, but they made a proper translation of that from the Greek with that idea of "It", simply because Paul explained in verse 37 that seed which is sown is NOT the body that shall be. And that "It" that is sown is about our 'soul' sown into a flesh body, but raised with the "spiritual body".
1 Cor 15:37
37 And that which thou sowest, thou sowest not that body that shall be, but bare grain, it may chance of wheat, or of some other grain:
KJV
Paul is trying to show the body that shall be, the resurrection body, is not a body of flesh (i.e., the original seed body). To make this plain, Paul reveals the two different dimensions of existence, the earthly vs. the heavenly.
1 Cor 15:44
44 It is sown a natural body; it is raised a spiritual body. There is a natural body, and there is a spiritual body.
KJV
1 Cor 15:48-50
48 As is the earthy, such are they also that are earthy: and as is the heavenly, such are they also that are heavenly.
49 And as we have borne the image of the earthy, we shall also bear the image of the heavenly.
50 Now this I say, brethren, that flesh and blood cannot inherit the kingdom of God; neither doth corruption inherit incorruption.
KJV
1 Cor 15:45
45 And so it is written, The first man Adam was made a living soul; the last Adam was made a quickening spirit.
KJV
And because flesh cannot enter into that Heavenly dimension, even Lord Jesus' body was translated to "a quickening spirit", and THAT is the actual glorious body of the world to come.