I thought so too at first. But the more I look at it, the more I think it's all the same candy green applied with three different degrees of heaviness (if that makes sense). The side panel has a light coat over a silver base, the rest of the car has further coats, and the dark lines around the side panel is more of the same applied heavily. Those dark lines are going to be tough, as they will be quite thin in scale and they don't have a hard edge. At least that's how it looks to me. I think I would try a candy or clear green over a silver base. Tamiya clear green lacquer might be a place to start, though there are proper candy greens out there. Worth spraying a couple spoons and see what it looks like. Oh, and I should sum up by saying I am NOT an expert on these things, so take it for what it's worth.
I always thought this was one of the coolest of the early floppers. Are you going to build it?