There are a number of different 914A decks out there depending on the application. Also, the decks before them were just 914 decks. I do not know if the applications and deck mounting kits are compatible for the 914 and 914A decks. Not all 914A decks are equal. I don't believe the deck on my 1530 will fit my wife's TC-23. Obviously the mower hang kits will be different as well. The early 914A decks did not come with the spring float kit that is standard on all the 914A decks now.
I would take your component # and serial off of the deck to your NH dealer and make sure the deck will be compatible with your tractor. Most of the NH dealers are pretty helpful and can give you the info you need to mount your deck. Hopefully the deck came off of a TC-21 or TC-24DA for everything to fit.