I've been following this and dug out this NOS rear sway bar I have.
It is natural finish but shows some traces of black paint...perhaps as a preservative.
Has part number stencilled on and
Grey paint/primer also evident near the brackets.
Very interesting
Does the grey primer look to be over some of that black paint ?
The one Walden did looked to have something on bar near bushing.
What’s tough is NOS parts often look a lot different than assembly line parts.
Need survivor pics also.