I think there is either a plastic or steel bearing dust cap. The centre of the disc is different depending on which cap is fitted. So it makes sense that there are 2 different types, but not sure about the change at the end of '82. Brembo catalogue shows a change in overall height, from 79mm to 82mm?
The change from 082163.20 to 082163.10 seems to all be based around the end, the way the front bearing sits and the addition of the big cap. I cant seem to figure out if it makes any difference? I would guess both would fit my stub axles and both would work. they also sold 082163.08 which was .10 but without bearings.. I think from the drawings.
Now I am fluent in Italian (Google Italian to English convertor) I have found all different ones available, going from cant find any to which bloody one fits! Going to take mine off tomorrow and have a measure.