Probably (likely) ex post facto. That is unconstitutional and would be argued during the appeal.
I'm betting that per state law that since the crimes were committed in the '80's he's subject to the laws in effect at the time - even though he was just convicted.
That being said this 'recovered memory stuff' is troubling. Much of it is horse poop. The so-called memories are created by the therapist.
A twelve or fourteen year old who cannot remember sexual abuse until he is in his thirties...and in therapy no less?
Aren't these registration laws retroactive?