Saw one guy had done a MK2b light conversion a while back with his MK2 Punto, it was featured on another site though ' PuntoPower.com' an Italian web site, now shutdown unfortunately due to inactivity from the owner
Think he had to change the wings for MK2b ones as well as the slam panel and bonnet, should imagine you may have to change the bonnet hinges too?. Looked ok, but tbh might have been easier to buy a MK2b? I should think they are cheap enough to buy now, usually see them pop up on eBay fairly often. Hope that helps!