Is there any raised relief on the part, especially for the dials? Or are they just round holes through the part?
If the dials have raised detail, I'd just prime the whole thing, repaint it and drybrush the details. If the dials are just round holes, I'd still just prime it, but get some instrument decals, like Mike Grant's (I use them, they're excellent) and use the decals for the dials.