LOL Tac

Well the Crown Vic is not really a Police Interceptor, but that`s another subject.

Nothing really different in the VIN. Plant, year, so on. If engine is different, that will be on the VIN.
Options real difference. Option codes will tell you every option on the car, and thats whats seperates any car model. (exp. Heavy Duty suspention = FE3 for 1988 Oldsmobile) Find the list in the trunk, deck lid, spare tire cover and so on.
I remember on a 1990 Camero Z28 the high performance option code was G90. One of the things included was the 275HP Corvette LT1 engine. (became standard engine in next Z28 body style)
Every police department that used that car as a Police Interceptor (Arizona was one) had the G90 package.