Have a look on YouTube. There are plenty of videos out there. The 1100 and 1150 final drives are almost identical in construction apart from Crown and pinion gear ratios.
The case is machined to a tolerance, the bearing is machined to a tolerance. Variations between the two are taken up with shims. Now it could be that your case was machined to such a high degree, that it did not need a shim fitted.
Provided the bearing that you replaced was exactly the same width as the one you removed, then If there was no shim fitted at manufacture, then it would not necessarily need a shim fitting at replacement. But, if it wasn’t then it would have needed shims fitting to get the correct preload.
Not for nothing do BMW provide a range of shims.