So ever since I got my 1979 280zx I've been trying to figure out whether it was a Grand Luxury model or not, which would give me just a little bit more information, So I bought a mint condition brochure for my year and discovered a few things for 79 models.
First, if you have these features in your car you most likely have the Grand Luxury package:
Cruise control
Power steering (in 2 seater, 2+2 was standard)
Power windows for both windows, and the auto up and down on driver side
4 speakers, instead of 3
Aluminum alloy wheels
Rear window wiper and washer
electronically adjustable passenger side mirror
and that cool computer checking system on the dash

This means if your car has those features then its probably a Grand Luxory, or if it has one or two of them, its probably lost a few of those things over the years
I'm pretty sure A/C was an option with any model
So from my interpretation of brochure the 79 only had 5 real options:
The Color you wanted
The Standard(cheap model)
The Grand Luxury(expensive model)
A/C
Manual 4-5 speed/Automatic 3 speed

Meaning if you wanted rear window wipers you had to get the Grand Luxury package with everything else or no rear window wipers for you.
Now for the disclaimer:
Sorry if this has been posted before but I've used this forum a lot and have been looking for a chance to give back some info.

 

 

What about the 80s model? (late 79 for mine) Similar thing?

 

Good info! I was actually trying to figure this out recently as well when shopping for a zx - I was pretty sure I was looking at a GL 280zx at the time, but then read something that indicated that they also came with power door locks . . . turned out to be incorrect, but these pre-VIN cars can be a PITA to figure out sometimes.

But anyway, the other way to figure it out would be via the differential. '79 Grand luxury's came with the more aggressive 3.7 final drive, so plug in the gear ratios into something like www.fbody.org/gears/, and see if it matches up with what you're spinning at different speeds. i.e. if your tach is spinning at 2900 rpms in 5th @ 65mph on an otherwise stock '79, you've got a GL.

Or at least, you've got a GL diff.

 

call msa with your vin and model # they can tell you right away.

 

Does that work with the pre-1981 vins? i.e. HS130-XXXXXX, not the full 17 digits.

 

I don't know but im gonna go out on a limb and guess this was probably the same up until they switched from that chrome column cover with horizontal lines to that black column cover with vertical lines.