The easiest way is to get the VIN and then go to Ford's website and do a VIN search on the VIN decoder.
VIN Decoder - Ford Truck Enthusiasts Forums
The year of a coach is based on the house and not on the chassis. For example a 2016 motorhome could be built on a 2015 or even a 2014 chassis depending on what the RV manufacturer has in stock at the start of the build.
Thor Forums
