I have never in over forty years in the wt seen ANYONE brought into the organization with a Bible alone.
Never, ever, never, ever, never, ever, never, never.
I remember once last year I was working what amounts to seldom worked territory up near Three Rivers, CA. I went to a door with an older brother and the person who answered asked a similar question. Could he and his wife learn from us using only the Bible? He asked because he had been burned by organized religion and had faith only in the KJV.The brother said, "SURE!" and I looked at him like he was nuts.
He set a time to go back and placed a brochure with him and told him to read it and he would be back in 3-4 days to review it with him.When we got back to the car so we could drive off to the next ranch, I asked him if he would bring me back because I wanted to be able to teach with only the Bible. Know what that old bastard said? He told me that he was not coming back. He told me to come back on my own if I wanted to but that I better bring the Bible Teach book. He said the Bible alone was going to lead those poor folks into trinitarian teachings and that I could wiggle the book in after a couple of visits.
I have known other folks who got really freaked out when the person at the door refused the wt or other publication and asked for us to use only the Bible. Seems most JWs are totally unqualified to teach the Bible. Hell, I can even remember back in the 1980s having Bible Verse games where someone reads a text and we have to say the book, chapter and verse. I was ok at it, but most everyone else sucked bad at it. I usually came in 2nd and one older sister won like 99.9% of the time....
JWs IMHO are totally dependant on wt publications and would fail miserably to explain any verse from the Bible without being able to flip open a watchtower or other book they publish.....