I don't recall the book being studied, at least not during the period from its release to 1993, after which I stopped attending meetings. But as Blondie posted, if it was WTS-sanctioned bookstudy material, they would have posted a study schedule.
I think we should just agree that, though may have been studied by some bookstudy groups at some times, it was never a Society-sanctioned study publication (how those bookstudy groups would get away with studying a book that they, not the WTS, selected is an interesting question. But so far all we have to establish that is the memory of some members of this board, whose memory may or may not be faulty on this topic).
That said, I do recall a time during the 1970s when bookstudy groups did determine how much material they would cover each week. Later, the WTS dictated that too by means of the schedule in the KM. But like Blondie, I cannot recall any time when a group was permitted to select which publication they studied.
But it is interesting in any case to ponder the Society's attitude toward their own publication. After all, it has questions printed at the bottom of each page. It clearly was designed with eventual study in mind. After release, did the Society indeed see some 'danger' in their own book? Did they simply think the 'friends' would not be interested in studying other faiths? The former seems more likely (lack of interesting material never stopped the Society from assigning such for study, to my knowledge). My guess is that, after releasing this book and having it in circulation for awhile, they perceived some kind of threat from it - which, if true, is laughable, considering the fact that it's their book!