That is it, except the difference is that my spindle is wider otherwise it looks nearly identical. The B/C drive is identical. The spindle covers up the access holes in the plate that go through to the drive's platter. You can see the bolts in the top image with the spindle. They are big, circular, and go through the plate and connect to the C Drive's platter. The holes in the drives platter in the lower image is what that big bolts go into. The spindle I have is wide enough to cover up about 1/2 the access hole.
I've thought about counter sinking those bolts so they are below the surface, but that's the rub, the plate gets bolted to the spindle first with countersunk bolts on the opposite side. I can do one, but not the other, brain hurts.