The receiver sight, the two-position side swing safety and the apparently Timney trigger are American aftermarket features added much later in the USA as such things were then unknown in Germany.
I certainly agree with the observations about the trigger and safety. The Lyman 48 is slightly more problematic, since the second model 48 used on the rifle was phased out after World War II, and would probably not be "added much later". Also the Springfield Joe mentions above, built about the same time, was fitted with the same model Lyman 48 sight. On the other hand, the inletting around the 48 base does not look as carefully done as that on the rest of the rifle.
