I think it's irrevocably separate. My idea was that no one is a law student and a pre-law student at the same time, so it wouldn't matter if they were different. I also didn't use to require logins. They got switched on accidently one day and no one complained, so I went with it.
There's still no logins needed for the Students' board, though someday they'll be required (I'm trying to make it easy for people to migrate at the moment).
It might have been a bad idea to make two separate boards, but I think it'll prove usefull in the long run. The two boards are supposed to have different flavors - one about life as a law school applicant, and one about life as a law student and job applicant. We just need more participation on the Students' board.