This is the Metal Helmet re-colored in black as requested. It will look different depending on which mod you use on it. Just added: version with every part of the helmet in black.

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!