ultimately, the RV MANUFACTURER has the LAST WORD as to the Year, Make, and Model of a motorhome THEY build.
The 'chassis' they buy to build the RV on, such as Ford or Freightliner, will certainly already have it's own 'VIN', with a 'year built' indicator, but that is NOT the year the RV MANUFACTURER uses.
Since a factory can purchase a chassis WELL before it's ever used to build an RV on, the chassis' VIN and 'year' have little to do with what the final YEAR MODEL is, as determined by the RV Factory.
You can have an engine with a 2006 build date, installed at Freightliner in 2007, with that chassis then having a 2007 build date, with time to transport it to the RV Factory, or have additions made along the way(common), and the time it sits on the factory lot, and then the factory decides that the 2009 MODEL YEAR is not starting - in which case this '07' Freightliner chassis is going under a 2009 Year Model RV.
There are some states that just will not try to understand how and why this works, and really decide that it's not generally 'their business' to care - they access a database for checking VINS, which ultimately goes back to the CHASSIS MANUFACTURER, and that's the 'year' they use, no matter what YOU might argue - although, truthfully, does it REALLY matter??
Your registration, insurance, and title have no ultimate long-term bearing on anything to do with the RV's value - as that is determined by the RV MANUFACTURER's 'year model' designation, no matter 'what' the DMV, State, or Insurance Company may try to say.
SMILE....it's all good! : )