Based on the body shape, it should be a short scale. There was a time when Alembic was willing to make longer scale basses in this body shape, but the balance doesn't work well. It is at least very highly discouraged these days. I would think that policy would have been in place by '90, but I am not sure.
It is truely a beauty, though. I really love the classy figuring of the top. There's a lot going on.
-Bob