Right. I kind of think it's a bit odd to use AA's BB as the primary text--it seems like that would not be maximally useful to friends/family of alcoholics. And any Al-Anon could attend an open AA Big Book meeting if s/he wanted to.
Way before I was ever in AA I loved going to AA meetings. Maybe that was a sign, lol. I always felt more "affinity" with the people in AA than I did with the folks at my Al-Anon meetings, but Al-Anon was my lifeline when I was at my most desperate in my relationships with alcoholics.