I actually didn't know about the black mounting brackets were offered OEM. I've tried to search it on realoem.com to see if i could provide a part number to the dealers locally here and no luck. When I asked them, they had no clue what I was talking about.
And the reason for offset was to avoid the center reinforcement bar, it just make the cutting of the hole from my original plate a little easier to access.
I agree, I like the black after seeing it.