About the silver/silver-gray paint. If we are talking about the surfaces of the fuselage and wings, then it is rather unpainted aluminum. Duralumin. This can be seen in early seaplanes. Unpainted aluminum.
There was a painted surface on the A5M1 and other carrier-based aircraft. It was an anti-corrosion coating. But I'm interested in seaplanes. And their coloring in niches and panels.
Can this coating or primer you're writing about be considered a prerequisite for aotake or not?