Did Nico Robin unlock Armament Haki?

2nd Possibility – NICO ROBIN DOES NOT HAVE ARMAMENT HAKI

There is the possibility that Nico Robin does not have Armament Haki. This could be artistic shading to imply a demonic presence, like Cavendish when he’s possessed.

According to this theory Robin’s limbs are not imbued with Haki because Armament Haki is drawn differently. It’s black with shiny spots along edges/on curves. This has a different gradient to it.

This is the real picture:

Here’s how Oda would have represented Nico Robin with Armament Haki:

So what do you think? Did Nico Robin unleash Armament Haki in the fight against Black Maria or not?