To understand those verses one must first understand it was a comment made in debating whether or not the dead were raised up or not and if they did what body would they be raised in.
1 Corinthians 15:35 But some [man] will say, How are the dead raised up? and with what body do they come?
Paul was explains it this way:
1 Corinthians 15:36-37 [Thou] fool, that which thou sowest is not quickened, except it die: 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]:
Paul goes on to explain that God has created different bodies for different purposes in His creation.
1 Corinthians 15:38-39 But God giveth it a body as it hath pleased him, and to every seed his own body. All flesh [is] not the same flesh: but [there is] one [kind of] flesh of men, another flesh of beasts, another of fishes, [and] another of birds.
Not just in living beings but in organic bodies as well.
1 Corinthians 15:40 [There are] also celestial bodies, and bodies terrestrial: but the glory of the celestial [is] one, and the [glory] of the terrestrial [is] another.
So there are different bodies and each body has its own glory (doxa). The glory of the living things is one type of glory and the glory of the celestial (epouranios) things have their own glory.
doxa
glory (as very apparent), in a wide application (literally or figuratively, objectively or subjectively): - dignity, glory (-ious), honour, praise, worship.
epouranios
above the sky: - celestial, (in) heaven (-ly), high.
1 Corinthians 15:41 [There is] one glory of the sun, and another glory of the moon, and another glory of the stars: for [one] star differeth from [another] star in glory.
Paul explains that everything, even the stars, have their own glory. He explains that the glory of the heavens is broken down into each individual body that has its own glory. And he says that in the same way that everything has a different body with its own glory that is how we will be raised from the dead. In a new body which has its own glory.
1 Corinthians 15:42-44 So also [is] the resurrection of the dead. It is sown in corruption; it is raised in incorruption: It is sown in dishonour; it is raised in glory: it is sown in weakness; it is raised in power: It is sown a natural body; it is raised a spiritual body. There is a natural body, and there is a spiritual body.
So you see Paul isnt speaking about different degrees of salvation but how God has given everything a body and that body has its own glory. Paul concludes that when we die our earthy bodies are turned to dust and a new body is raised from the death of the old one just as it is with seeds. Our earthy bodies will serve us no more and we will be given new incorruptible bodies.
1 Corinthians 15:49 And as we have borne the image of the earthy, we shall also bear the image of the heavenly.
So how do you interpret those verses?