With rolling line changes it usually is fairly seamless between years.
HL makes changes as they go, unlike the auto industry that saves most changes for the coming years "new" model.
My 2011 BH was made right at the end of the model year and I have seen 2012's that are exactly the same.
For the most part, it is only a number on the coach. It doesn't always mean it will be significantly different than a previous year model made one week earlier. JMHO
Trace