I'm no expert here, but usually the VIN on any vehicle will be used to describe its model family as well as engine family. Because the HO is an optional powerplant unto itself, chances are that the VIN would indicate things as such. Thereby allowing the RMV monkies the chance to put on the brakes when you go to register it in another non-HO state. I wonder if the law would apply when taking delivery of a new truck only, versus buying a used '03 HO from a private party?