How many of us are there? Owners of Dodge based RV's?

This is very common in Class C motor homes. The chassis is built in one model year, the remainder in the next. In all cases the standard in the RV industry is to consider the MH to be the year of final assembly, just as a car with an engine from the year before is considerd to be the year of its final assembly.

In some states, the registration goes by the year of the RV. In others it goes by the year of the VIN on the windshield, which will be the year the chassis is built.