Tammy,
Good question.
I have only observations here. My Father has been an elder for 30+years. His knowlege of the Bible was zero until he started studying with the JW in the early 70's. Basicly the WT and publications gave him any knowledge he has. There was not any other 'outside' information on our bookshelf. With the following exceptions. A king James version of the Bible. This was allowed only because it was occasionally referenced by the WT Society.
Also, yes the JW's can turn to any book of the Bible and quote alot of scriptures, backwards and forwards.. kinda a byproduct of three meetings a week for years and years... but would have a hard time telling you the meaning on a parable without looking up a WT article on it first.. kinda telling.
Peace to you
CL