First thing I noticed is that some of the interior trim is black, door cards and trim in the rear hatch area etc.
The rest is blue/grey, seats, dash, carpets etc.
I'm betting the dash has seen better days and so has the carpet dash cover!
The leading edge of the bonnet is very rusty as shown in the pics and would not really be salvageable.
Check for rust in:
the battery tray area,
look under the carpet in the drivers and passengers footwell,
sheet metal around the petrol cap,
check around the windscreen and rear hatch,
chassis rails can get pretty banged up as well and can cause problems when it comes to getting a roadworthy
Being a series one 280ZX it's going to have a drag link, steering box set up as opposed to the rack and pinion steering in the series two.
I'd spend a little more and buy a decent example and save yourself a lot of work at the end of the day.
Good luck either way!
Something for you to look over
Both of these are series two cars
https://www.carsales.com.au/private/details/Nissan-280ZX-1984/SSE-AD-4712740/?Cr=3
https://www.carsales.com.au/private/details/Nissan-280ZX-1983/SSE-AD-4394662/?Cr=1