Wallsy, sorry for the belated reply. Your truck is imported so has the US diff code.
That makes it nice and easy to buy parts from the US as your codes, and VIN, will go straight into the US parts suppliers computers to positively identify the exact model of your truck. If you ever go to a local stealership you'll give them a real headache when they try to run your vin.

Anyway, good pick up on the US LSD for your vehicle. Did you check if the diff that you're buying is also a 73 (i.e 3.73 final drive ratio) with a 10 5 (10.5") ring gear?