Well, everything will be made clear in a few days. I don't think anyone should be worried about it dropping, whether they got the status for opening the card or renewed for spending 10K. The site for the card says pretty clearly that those who earned Gold prior to the merger will get Platinum status through 2019.
It's most likely the case that Marriott cannot differentiate between the first year free or the 10K renewed status, as the system would likely just involve Chase notifying Marriott that a criteria to receive status until date X has been met and Marriott granting it accordingly.