Glad you've found a contact for your grandfathers shotgun parts. Those parts could be very difficult to find.
I had to use my map finder to learn where Liege was located in Belgium. I've never been there. My wife and I traveled through the coastal area of Belgium two years ago on our way from Callieu, France to Amsterdam, Netherland as we vacationed via motorcoach on a tour of central Europe. In July of this year We plan spend ten days in the south of France near Nice.
"If it's worth doing, it's worth doing right".