I believe the current plan is that the current sharklet A321's will be fitted with an extra 5 seats before the start of the summer season to bring them in line with the existing A321s. This is to make it easier with regards to aircraft swaps throughout the summer.
The A321s which are yet to be delivered will already be fitted with 220 seats.
The company have recently confirmed to its staff that NCL will indeed have 2 brand new A321s based there for summer 14.