Funny you should mention the pilothouse being cast. I had the same thought last night as I didn't think it possible to get iron rails to work together for that conical shape. I have sanded it smooth. And yes, I have started painting in Tamiya Gunship Gray which is the darkest of brands between Modelmaster and Tamiya. And in modeling there is that thing called "scale colors". In that as the scale gets smaller, the colors get lighter.
The gunports, again I may be over thinking reality, I know they were absent doors during the March 8th and 9th battles. I'm speculating that maybe down the road, doors were added. I dunno. I have the gunports opened on the starbaord side and receiver blocks behind to accept cutoff barrels. I'd love to put doors on as it makes my life easier as I can pick and choose how many barrels to have to make.