If you get it, you will get the bonus. But it will likely be declined with no credit pull.
You can get the Gold Mastercard (with different benefits, therefore a different product) and get the 30K.
Very few have managed to get 2 Platinum level (including AMEX Select) cards since Citi stopped the 2 browser trick around the end of January, and those who did managed to get a manager to bend the rules, IMO.