Really nice rifle, a work of art thats for sure.
I hope my eyes are deceiving me, but I can see big problems with the rear tang and how it has been lowered for a more pleasing top line of the wrist.
If you are going to make this mod then the slot has to be flared out considerably to prevent the cocking piece riding up the tang and jamming.
You simply cannot have this situation on a DG rifle.
Most Mauser smiths have gone right away from filing down the rear tang, preferring to leave it as original.