Its the blue paint that gets me. Its not that metallic blue/green you would normally associate with interior colors on a Japanese aircraft, its more like a light blue. I was thinking a gun mounting of some sort.
The part with the hole in it was at one stage covered with aluminum plate, like the part with the symbol on it. Now if this was in the wing they wouldn’t bother with such aesthetics would they? They’ve covered it because it must have been in prominent view or in an environment where the pilot was operating.