Mulching kit for 54" deck

[jasz]

My kit was on the back order and finally it arrived yesterday but...

They shipped Mulcher Plate for 42"cut mover (Kit No. MP42A). Does anybody can clarify couple question?

1. Does 42" Mulcher plate fit 54" deck?
2. Do I need a special mulching blade or original blades on my deck will do just fine?

I think they sent me a wrong thing but need to verify that before I start to complain to Speedway.

Thanks for any suggestion and/or advice.