This is how evidence for bona fide changes looks like:
Room Conversation with the Mayor of Evanston — July 4, 1975, Chicago:
Tamala Krsna: “Farming, cattle raising and business are the qualities…”
Prabhupada: They are not cattle raising, that was…
Tamala Krsna: Cow protection.
Prabhupada: Cow protection. It has to be corrected. It is go-raksya, go. They take it cattle-raising. I think Hayagriva has translated like this.
This change is – contrary to all the post-1977 changes – Prabhupada-approved. It first appeared in a 1976 reprint of the 1968 abridged edition of Bhagavad-gita As It Is.