You think there are a few too many rusty brackets and fittings for that car to have spent its entire life in SoCal? I think so. When you look at the bolt heads to the fuel tank closing plate as well as the studs left where the air deflectors would be, the bracket just behind the accumulator opening and a number of bolt or screw heads in the engine bay, it just doesn't look quite as "rust free" as you hope it would.
I'd find out if the alarm works or not and what it ties into that got modified. My experience with these classic car dealerships hasn't been good and while they might not try to purposely screw you, they might inadvertently do so anyway just from their own ignorance to what they are selling.
Plastic coolant bottle has been changed out, which is good. So too has the three-way valve on the air intake. It has the cold only performance duct. Does this matter when smog'ing a California car? I only ask because if it does, one might start to question whether it indeed does have a valid smog test pass.
Missing the outside seatbelt bolt cover on the driver's side. Might ask why there are wires hanging down from the centre console on the passenger side. People don't generally go in there unless they are fixing something or sorting a problem out. Not a for sure issue, just something to follow-up on when it catches your eye. Where did the driver's side floor mat go?
Or if going through the expense of shipping a car to NZ anyway, you might see about paying DMCCA to go look at this car BEFORE you buy it and check it out for you. If you end up buying it, maybe that cost gets rolled into more work they can help you with prior to shipping. If you don't buy it because they don't like what they see, it ends up being a well spent $300 or whatever to rule a bad car out.
And if NZ gets the warm weather like I presume it does, finding out what it will take to get the A/C system working would be smart. I would not assume it will take an existing belt to be reinstalled and a $50 can of Red-Tek12 to top it up.