Star is a one design class, ok. Robert Scheidt developed a boat designed by Juan K and Lilia Boats from Italy for the next Olympics. I don't think you can do that in a real one design class.
470 is a one design class, ok. I saw in a manufactor site that they developed a new mold, with a new deck and some small stuffs to improve the performance of the boat.
Only Laser/Radial and RSX boats and boards are manufactured by ONLY ONE MANUFACTOR, they supllies the boats and boards for the Olympics, the rest of the classes you can buy the boat from any brand you want to, buy a mast (or masts) from any brand you want to, buy sails from any brand you want to.
One design here is just an idea, but there are some differences from boat to boat, within the limits of the rules. That's what I meant to say.