After JS had the First Vision he checked out Catholic books from the library. God also had him translate ancient documents, a major being the BoM, and another one is the Book of Abraham. When looking at not the most reliable sources JS did not call it apostate and never looked at it again, as he continued to check out Catholic books from the library. But I believe he and we should look at these sources to gain the truth from them that they have, as JS taught we should find truth everywhere no matter where it came from and make it Mormon. Truth is confirmed through the Holy Ghost not by the man who said it. (Heck eve the Devil says truth, but he then tries to tie it a lie that he is going to tell you.) One thing I have noticed with myself, and I believe it happened to JS, reading what other people say, even if it is not true, can get you thinking and cause you to be inspired to truth because now you are thinking about it and inquiring God about it.