Yep. You are right. My ute has a build date of 7/85. It is interesting to note as well that it has no datsun badging on it - all Nissan logo's.
Not sure what else they may have changed mine has retractable belts, park brake light on top of dash, tacho, disk brakes etc.....
As MadTimo asked (sorry about the car by the way) how do tell what diff is in it??
Also my odemeter has stopped working. Speedo still works and the "meters" dial still works but nothing else. Is this common - can it be repaired?

I've pulled my speedo apart, and reset the miles years ago. It's not hard. I bet if you pull it out, and run a drill on the speedo (in the correct direction), youi'll see what's bent or broken to stop the odometer ticking over. Try and roll the dial over by hand. Worst case scenario is find another speedo. Sounds like you've fixed it how many Japanese would like it to come from the factory...saves them tampering with it before exporting it to Australia on the grey market.

Ther best way to figure out your diff it to do this...Jack one rear wheel up in the air. Put a piece of tape on the sidewall of the tire. Put gearbox in neutral, Put another piece of tape lengthwise on the tailshaft. Get someone under the car, to count the number of times the tailshaft turns for each rotation of your wheel (Which you turn exactly 10 times). This is nearly impossible on a FWD car.

Divide the big number by the small number and you'll get your ratio.

Good Luck.
Chris

On the subject of differences, what diff does a 74 or 75 ute have? All the 1971-1973 utes had the H145, right?

My Japan parts book shows all 1976 and newer B120/B122 as having the H165. Does that seem to fit Aussie utes too?