My 109 had disco axles, the flange, drive shafts and bolt patterns are all totally diffo.
Stuffing disco flanges on a series axle tube is not all that easy, even if you have a toolroom.
The disco axle does go on the series, but you need to grind off all the spring and shocker mounts and make some new brackets, or you can modify some standard disco lifting mounts, and then you need to fill up and re-drill the flange threaded holes in the axle tube, as the series diff nose angle is way diffo, largely down to the fact the the series is effectively a trailing link suspension and the disco leading, meaning the geometry is all screwed up.
As hinted there are some rare examples of range rover stuff fitting, and you can get very exotic sally front axles with disc brakes, but you need a mortgage to buy them.