Expert modeler John Youngerman sent copies of photographs of what appears to be the builder's model of the cruiser
Gotland. The main deck was wood-planked. In the model, the superstructure deck are red or black. Particular British and Russian warships had brown decks but red is unusual.
In the photograph of the actual ship, the relatively light color of the upper decks does not match the centers of the aftermost life rafts. This photograph seems to establish that those colors were different. The amidships liferafts appear to be of one uniform color, similar in brightness to the decks.
From this I conclude that when photographed here, the brighter areas of the upper decks were not red. Has anyone information about Swedish naval policy about deck colors?

If humanity wishes to preserve a planet similar to that on which civilization developed and to which life on Earth is adapted, [atmospheric] CO2 will need to be reduced from its current 385 ppm to at most 350 ppm.
Dr James Hansen, NASA, 2008.