The cars are being built now. Technically there will be 137 cars labled as 2015 MY and the rest as seen above will the 2016 MY. To my mind its all one model year as they are the exact same car with the exact same options. And since these cars will be produced through the summer of 2016 in my mind they are all 16 MY vehicles.
Interesting note, it seems as if Ford is building MY 16 350's intermingled with MY 15 350's. Has that happened before?