You must receive your C&E prior to going to the CK, but it doesn’t have to happen during mortality, that can happen as spirits as well.
2 Peter 1:10
10 Wherefore the rather, brethren, give diligence to make your calling and election sure: for if ye do these things, ye shall never fall:
The Prophet Joseph Smith counselled:
Oh! I beseech you to go forward, go forward and make your calling and your election sure; and if any man preach any other Gospel than that which I have preached, he shall be cursed; and some of you who now hear me shall see it, and know that I testify the truth concerning them. (Teachings of the Prophet Joseph Smith, p. 366.)