It is, but depends on image, if you for instance pick the surface of items within already lit scenes, the actual "true" color may be incorrect since the color of the lights in the scene affects the surface per that light attribute..when you pick it with pick color tool, and your scene may have the lights differently.It's a good idea to find a real reference photo with the item and use the "pick color" tool from the image.
0,0,0, ultimate black, multiplied by other scalar or color will still remain 0,0,0..
So color temperature of sunlight or other sources will result in different colors in the reference image, so choosing that would be a bit wrong, unless you match that real life photo color temp.
So best is probably to find a texture that is as much as possible within the "clean white spectrum"..I suppose? and evenly lit.