I just bought a new LX2610. The mid-mount mower deck it calls for is a RC72-30BB. It's predecessor the B2650 took a RC72-30B, I have the opportunity to purchase this one used (barely) at a super reasonable price. Does anyone know what the difference is on these two decks? Not sure if it is just an improved model but the old one would still work. I could not get a good answer from the dealer.