This is a black re-color of the metal armor but with the leather parts left untouched as requested. If you would like to see what the metal armor looks like with different material mods, please see this image.
1. Place the texture folder into C:\Program Files (x86)\Steam\steamapps\common\Fallout 4\Data. If you already have the texture folder, place the contents inside into the folder.
2. Open the Fallout4.ini file in your Documents folder: (…Documents\My Games\Fallout4) and find the line: sResourceDataDirsFinal
Replace it with: sResourceDataDirsFinal=STRINGS\, TEXTURES\ and save the file!