This Mustang has been registered at least twice that I know of in New York State via the "problem" serial number. So what's the big deal. Whatever the number is it relates only to that specific car! Federal document--NATIONAL HIGHWAY TRAFFIC SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION
PART 565--VEHICLE IDENTIFICATION NUMBER REQUIREMENTS--Table of Contents
Sec. 565.1 Purpose and scope.
This part specifies the format, content and physical requirements for a vehicle identification number (VIN) system and its installation to simplify vehicle identification information retrieval and to increase the accuracy and efficiency of vehicle recall campaigns.