Ones I have looked at, that were mounted by G&H, had the base soft-soldered on with taper pins and large head screws. The heads and pins were also soldered in place and all this was dressed down and then rust blued. Then the screws and taper pins were all but invisible. Generally the screws and pins could be seen inside in the broached lug ways, as these surfaces were polished bright after blue.
That is a nice looking rifle.

Dennis Potter