Immediately after I told the elder that I have (or had) some Rutherford books and read them, the elder angrily asked me where I obtained them.
This and many other similar experiences with angry JWs, including Randall's tale of the bonfire, leads me to believe that there are many witnesses fully acquainted with old literature. Yet they don't leave. Why? Position, prestige and business. Witnesses are not always witnesses because they wish to serve God and truth. A minority have other motives.