Bhagavad Gita As It Is 1983 is correct edition to have and not the 1972 edition.

Bhagavad Gita As It Is 1983 correct edition, Chapter 2 text 12-

"Never was there a time when I did not exist, nor you, nor all these kings; nor in the future shall any of us cease to be."

Bhagavad Gita As It Is 1983 correct edition, Chapter 2 text 20-

"For the soul there is neither birth nor death at any time. He has not come into being, does not come into being, and will not come into being. He is unborn, eternal, ever-existing and primeval. He is not slain when the body is slain."

The incorrect nonsense 1972 edition of Bhagavad Gita As it Is, wrong includes-

"Nor, having once been, does he ever cease to be," which wrongly indicates the soul had a beginning, when infact the soul has no beginning or end. 

So please avoid the 1972 wrong version of Bhagavad Gita As It Is that immature sentimental devotees are attached too, and please read the 1983 correct edition of Bhagavad Gita As It Is.

Hari Sauri dasa explains Book changes-

https://youtu.be/T2OGZhdxGWE

Should Book changes be explained?

https://youtu.be/d9dmpexlB4I