Zinc Chromate from the factory

Has anyone ever seen a Z that looks like the body was dipped in Zinc Chromate by the factory? I have a 74 260Z that appears to have had this done. I was looking at a 73 240Z that was being stripped down for restoration and there was bare metal under the tar boards. On mine, Zinc Chromate under the tarboards, paint, seam sealer, you name it. And it's done a great job too as my Z has very little corrosion. The battery tray looks like you would expect though, deep pitting and all.