Its not really that hard to find these wheels in unpolished condition.
They are spun. Light and weak so you have to inspect them closely for cracks. Fragile wheels.
They may look like the tougher centerlines but the similarities ends there. Centerlines are forged, heavier/ stronger.
Powder coating would just remove any 1975 vibe the wheels have. Stick with finishes as they were back in 75 or it will make the car look like a fake.