This is a very common question within the RV industry, not just Forest River. The chassis of a motorized product is purchased from a chassis manufacturer (Ford, Chevy, Workhorse, Freightliner, Spartan, etc.) as an "Incomplete Vehicle" (with an established chassis serial number). When Forest River completes the vehicle, we assign a model year and a Forest River serial number to the coach portion. The RV industry and chassis manufacturer model years change at different times. For example, Forest River may introduce the 2002 model year unit in June of 2001, but the chassis manufacturer doesn't introduce the 2002 chassis until September of 2001.
Because Forest River "Completes the Vehicle" and assigns the model year, the value of any Forest River unit is determined by the model year of the Forest River RV, not necessarily the chassis. This may vary by state.