What have Jehovah’s Witnesses historically believed regarding the serpent in Eden mentioned in Genesis chapter 3?

YES – The Watchtower, June 1, 1964 p. 352 – Questions From Readers

It, therefore, is reasonable to conclude that before God cursed it the serpent possessed legs that elevated it above the ground.

NO – po (1974) chap. 5 p. 59 pars. 15-16 God’s “Eternal Purpose” in His Anointed One Is Formed

“Upon your belly you will go and dust is what you will eat.” This was not a curse upon the whole serpent family. Seemingly God’s words were addressed to that one literal serpent.

NO – The Watchtower, June 15, 2007 p. 31 – Questions From Readers

The Bible does not specifically state that the animal used in tempting Eve had previously had legs but lost them. While the wording of Genesis 3:14 might lead some to think so, we need not necessarily conclude that prior to this curse, serpents had legs.