Well, I could always paint over it!
But I do want whatever color it ends up being to be really dark -- like, almost black -- hence the black base coat. Given that, I'm strongly leaning towards a dark grey at the moment... Once I get the dark purple paint I intend to use for the upcoming project(s), I might have to do a small side-by-side comparison on the figure's back to compare.
Anyway, barring any minor touch-ups, here's the finished armor!
Now all I need to do is pick out a color for Shredder's torso, drybrush that up... and wait until I can score some Black Panther boots to proceed. Ah well, I have some ideas for minor projects to keep me occupied in the interim...