It is a WWII. They are getting hard to find these days. It has the nice thick and soft wool not found on coats made after 1979. You are lucky to have it come into your possession. With that coat, I would definitely either move the buttons myself, or have someone do it for me. There will be a unique zig zag pattern of stitching holding the buttons on. You can follow that pattern for the authentic look, or do it another way if that is too much trouble. If you do it yourself, it might be a summertime project, as it will take a while. Also be careful to not sew through one of the exterior or interior pockets. Congratulations on a good vintage find.