The Dutch Royals or other Senior Dutch government officials are on island for the opening of the departure hall tomorrow. The Dutch 737, mostly used for transporting the Royals is on the island. PH-GOV are the plane tail number. The link below gives a detailed configuration of the plane.
I tried to see it on the Maho Beach Cam, but couldn't find it. I wish you could zoom in on that camera. Maybe you can if you have a premium subscription.