I have the centerboard version of the Oday 30, too. It is not weighted, but it is not neutral buoyancy, either, and can use a little help in terms of mechanical advantage to lift it. When I bought the boat several years ago, it had a 2:1 tackle on the cabin top to give additional purchase, and wasn't too hard to raise, but sometime later, since I was adding self-tailing cabin top winches for spinnaker halyards anyway, I ran the tail through a clutch and then to the starboard cabin top winch. Now raising the board is really easy. Here's a picture of the centerboard:
On the same subject, be careful about using a Nicopress fitting on the bottom of the centerboard pendant. After having to replace it every 6-8 months, I suddenly realized it was acting as sacrificial anode, and being eaten away just like a zinc. Next time I replace it, I'm going to try a stainless fork.