If you buy a new RV, it's the "Certificate of Origin" generated by the manufacturer that determines the model year. The chassis vin does not determine the year nor does the year it came out of the factory. It's whatever year the manufacturer decides to call it. It's not unusual at all for manufactures to build motorhomes on last years chassis and the "Certificate of Origin" that accompanies the new unit reflects a current year. When that happens, it is titled as the year on the CoO, not the chassis VIN.
PS- now that being said, it does not preclude a DMV clerk incorrectly looking at the chassis VIN and putting the wrong year on the title. This can, however, be corrected with a bit of vigilance and persistence at your local DMV. (Ask me how I know!)
Days camping (2015)----88 days
Days camping (2016) ---110 days
2016 Wildcat MAXX 28RKX (33' TT), 2007 13' Scamp
2015 Ram Laramie Hemi
30 years RV'ing
12 different RV's