The only thing the VIN will tell you is if it was originally a Formula ("U" in position 2) and the original motor that came in the car.
http://www.transamworld.com/2genvins.php
The Data Sheet - originals were placed both under the passenger rear seat cushion and on top of the gas tank - will show all the RPO codes that designate the transmission, color and other options. This by far is the most reliable source of information and will show the VIN so you can match it to the car. You can also get trim codes from the Data Plate attached to the firewall.
To my knowledge, all rear window louvers (metal or plastic) were dealership or aftermarket add-ons. People either love them or hate them. I think black ones echo the rocker stripe on Formulas very nicely, but they've been known to rattle and vibrate at speed and cause damage if they come loose from their mounting tabs.