If the hull number is not on the starboard upper stern then it has either been removed or damaged and gel coated over. i confirmed with the builder this morning. This is the only place the law allowed it and it is a non negotiable. I would be careful as this seems unusual. To register a newly built boat the VIN verifier sees these numbers and fills out a form that is used for documenting the boat or DMV registration. Does the owner have any original documents etc. what is the year, beware you could be looking at a stolen or previously damaged boat.