We had the stroller on the Magic last December and it was brand new too... Or at least that clean

I believe there was a $100 deposit that was put back on the last day when we returned it.
It was the Peg Perego Aria. The ship was full and we had no problems getting a stroller the first evening, but I would suggest going to guest services as soon as you board.
Also, we were able to take the stroller in the ports including CC.