Yes you can retrofit the paddles -
The airbag is the same for both styles of wheels. You would need a new wheel rim though, with the cutouts for the paddles. Obviously you need the paddle set too. Then you would most likely need a different steering wheel slipring with the contacts for the paddles. And after that, you'd need to get the cabling from BMW, or make it yourself, to hook up the new slipring connector to the gearbox slave.