I disagree…most late war U-boats (of all classes) were hardly finished when they were pressed into service, some never saw a coat of paint in their short lives, nor anti-fouling of any type and some never even got as far as modifications or upgrades, or any maintenance whatsoever.
These boats were practically thrown in the sea as the last nuts and bolts were being tightened up, a crew then hastily assembled, and then sent out to meet their fate, whatever it may have been. They would but very rarely have ever seen a dockyard again, and due to this poor maintenance programme, it’s extremely likely that the rust and the look of disrepair would soon have taken a firm hold on these vessels.
I would hazard a guess and say that the U-boat in the pictures is probably not that far out in it’s depicted colour scheme of rust, dents and general state of crappiness.
Rich