It is indeed.
This video features the Unimog milt apps - Total 36min Min 32 & 34 shows the 421.128 version we had, rest of the video is showing the truck with the same engine, gearbox & diffs which MogFather is running onn - this variant is indeed the most capable off-roader among the mog family!
Sadly, I recall missing out an original 406 Freightliner in Tarnool, when I reached there the engine & cab was removed but it still had rest of the accessories & when I went back to get that home, it was already history 
//youtu.be/UjoqlcV7YG0