if by hubs you mean the bits the bearings sit in and the bits the calipers bolt on to, then they are the same on all the cosworth branded versions

if you mean the bits that go through the hubs and have the big fuck off nuts screwed onto them, then you need 2wd cos ones as they aren't compatibale sizewise with anything else

so, to recap:

2wd diff neds 2wd cv's and 2wd shafts bolted onto 2wd outer cv's which then go into 2wd output shafts

if you have the 4wd stuff then it's virtually the same (other than the diff ratio's, the lsd's and the shaft lengths) to every other sierra with a 7 inch diff, including the xr range

various granada's and sierra's also ran with 7.5 inch diffs which is where the shaft lengths vary from side to side 18.5 inch, 20 inch and 20.5 inch