Hi,
2wd were non vented, same as XR4x4.
4wd were vented.
I think I may have some decent but old (maybe only one of each) 4 wd and 2wd discs and 2wd calipers and carriers etc. (pair) here if you want to mock something up. I don't need anything for them but you would need to cover the post as they are heavy unless you travel from Birmingham to Hindhead (150 miles???)
The calipers are in good condition as I refurbished them a while ago.
The hubs on a 2wd are slimmer than on 4 wd too.
The diameters are the same but cannot remember if 256mm or not.