Yep, cut-off was in the mid-90's. I do not understand why there was ever a reason for a sliding gooseneck, but my '89 had one. Catalina Direct has a retrofit kit available, but the P.O. of my boat simply drilled and tapped two holes in the base of the sail track groove. Installed a socket head cap screw in each hole with the slide captured between them, effectively locking the gooseneck in place.
I have a boom vang and Boomkicker on my boat - neither of which will work properly with a sliding gooseneck. Not really sure of why anyone would want a sliding gooseneck in the first place.