The linked website notes that they are backordered with an expected two week delay. So at best, that is a definite "maybe".
My search for the 15 round magazines found nothing available for immediate shipment. So there is no surplus of the 15 round magazines. And that could be the thing that holds up immediate availability of the complete package.
So I will wait until I can get what I want. The dealer says he checks his sources every morning.