I did it, downloaded all files new, and when I install it I can see it isn't unpacking the KT gunsound files. After the installation I unpack the downloaded KT-soundpack in the DLC folder, and there is one file to overwrite. In the promted window you can see, that the file, which will be overwritten, has a different size and date then the one from KT. If the installer would unpack the files correctly, this files should be exact the same.