The VIN will tell you the model, body style, engine and a few other things.
In 84 it goes as follows:
1st Digit: 1=Made in USA
2nd: G=Made By GM
3rd: 4=Buick Motor Division
4th: Restraint System
5th: Model Code - K=T-Type/Grand National; M=Regal Limited; J=Regal
6th & 7th: Body Style - 47=Coupe; 69=Sedan
8th: 9=3.8l/231 V-6 SFI Turbo
9th: Check Digit
10th: Model Year - E=1984
11th: Plant Code
The rest are sequence #'s
The VIN does not differentiate between a regular T-type or the Grand National
The way I understand it to be is the T-Type was an option for the Regal and the Grand National was an option on the T-Type; so in effect the GN is an option on an option because you can't get a Grand National on a standard Regal.
The only sure way that I know of to check if you have a true blue(black really
) GN is to look at the RPO sticker in the trunk, as was mentioned earlier. The VIN on the RPO should match the VIN on the dash and everywhere else. On your RPO sticker it should have the WE2 option. If you've got the WE2 and everything matches, don't worry about what the DMV calls it. My GN is registered as a Regal, that's it.
I hope this makes things clearer rather than more confusing!!!