hi hubert,
imho, BEFORE your baptized, you can ask anything you want. its after that you get yourself into trouble.
as far as i know, you can read any jw publications as long as they are jw. many older kh have these publucation right in their own library. in some you can sign them out and take them home.
i don't think you'll find that its "written" anywhere that you can study or as ???'s about older jw dogma.BUT, its sorta like beards.....no, its not "written" anywhere, but if you start to grow a beard, your gonna hear and experience some really cold attitudes, loose priveledges, ect. maybe even get shunned, unofficially.
yet, its not written rule! i know i did lots of research on this while in, and couln't find anything that would stop me. untill i actually started growing one. holy moly. you'd a thought i had been bagged in the redlight district.
i think you'll find that while unbaptized you may ask away, your supposed to. after, your gonna get into hot water. questioning anything about the society, olde or new is taboo.
harold