Note that the color you get for black in LPub4 is going to depend on the data in ldconfig.ldr (assuming you haven't disabled ldconfig.ldr usage in LDView). You can tweak the RGB value used for black by editing ldconfig.ldr and changing the VALUE RGB and the EDGE RGB to whatever you want.
I seem to remember that official instructions used a special edge color for black parts to let you know they were black instead of dark gray. Since you have control over both the color and the edge color in ldconfig.ldr, you can tweak them both to your heart's content until you find something that matches what you want. And you can do this for all the colors in there if you want. So if you find that black and dark gray look too similar, but black is how you want it to be, you can tweak dark gray. (Make sure to back up your file if you make any changes, because installing a library update will overwrite your existing one.)
I seem to remember that official instructions used a special edge color for black parts to let you know they were black instead of dark gray. Since you have control over both the color and the edge color in ldconfig.ldr, you can tweak them both to your heart's content until you find something that matches what you want. And you can do this for all the colors in there if you want. So if you find that black and dark gray look too similar, but black is how you want it to be, you can tweak dark gray. (Make sure to back up your file if you make any changes, because installing a library update will overwrite your existing one.)