OK! I have an UPDATE!
I went to see the truck today. Overall, it was largely in line with what my thoughts were from the small amount of info on the ad.
First off, i don't think this is actually a genuine Nissan/Datsun Bushmaster. It has a plaque riveted to the dash stating "Long Rider Special Edition". It does not have the badge for Matrix3 like the US conversions seem to have. I cannot seem to find any more information on this. But the conversion is also not a hack job. It has been well executed and looks professionally done(and done at the time of the purchase in 1986)
The truck is clean, straight and mostly complete. There are a few little bubbles under the paint, but largely it has a small amount of rust or corrosion. There is some rust(maybe surface?) in the floor pan in the drivers side that could be problematic, but thats all i was worried about.
A few things i noticed that i was surprised by: it has a sunroof!(scary thought considering leak potential). It is factory in this light Blue colour(haven't seen that colour before). It has definitely had a respray at some point but in a very similar blue tone only metallic. It has black and grey doorcards however, which i expected to be blue as i've seen in other older Datsuns.
Replaced(?) bucket-style seats(in great shape as well as the rear bench)
Undercoated undercarriage at some point which has eliminated most of the rust
Missing the exhaust/muffler past the cab
Missing spare wheel
Grill is in the car(not installed)
Spare headlights/tail lights in the truck
Engine bay is dusty but pretty clean considering. Oil isn't murky or white. Clean semi-transparent black oil.
Turns over cleanly with no knocking or strange sounds
Overall, largely complete minus a few badge re-sticking jobs and installing the rear glass(door)
I also managed to (loosely) negotiate the price down from $2400 to $1500. So that makes me think if i show up with about $1200 cash that he'd take it. It will roll out of the storage space and onto a trailer. I just don't know if its going to be a real headache to either get parts for or to get up to drive-able spec.
Keen to hear all of your thoughts!
Heres some photos i took(super dark and cramped storage space)
for album of photos!