Ding,Ding,Ding...we have a winner.
Someone got creative with a stamp kit and likely a fabricated/altered title from another state and got semi legit paperwork for a (possibly) stolen or (perhaps) rebuilt or salvaged car.
If the guy doing this had any brains then he should have used the 383 engine code (H) along with an actual B-body plant code (A,G,E) to avoid raising any more red flags then a car with no VIN tag already would.
Trying to pass off a car with no VIN tag as some sort of factory special build with a motor never offered from a plant that never built B-bodies is something a Chevy guy would do.