Taking off one layer of paint is tricky. It can be easier, if the painter did a poor job prepping the surface, prior to their outer layer of paint. But if they did a halfway decent job, and the outer layer of paint is good and cured because its years old, it will be a challenge to remove and leave the underlying layer in tact.
I've tried this idea before, and had mixed results, with media blasting at lower pressures. Another attempt used acetone and a rag to wipe off of outer layer of paint. In both cases, the lower layer of paint sees some damage and may look okay for a survivor car, but ugly on things restored.
One of those projects was a 1970 Barracuda grill someone had painted black. Low pressure media blasting did a great job, but the underlying ardent was too damaged to be usable as-is.
If you're going for the flat black rear panel, and the rest of the car is pristine, I may recommend you sand it down by hand, as chemicals may damage surrounding paint. Sand it smoothe and get her painted right.
But it seems a real, real long shot to remove the ardent silver layer well enough, and to keep the underlying black layer in good enough condition it will be usable.
