Katuna.
Your image from das Boot seems to be pretty close to the real thing, except the not painted parts like the push rods are a bit too rusty. The engineroom crew of a submarine does not differ from normal engine room crew, on boring long watches they spend a lot of time shining the engines, using emery paper and polishpaste. Brass and steel were shining and not painted. It is unfortunate that the old U 995 has blue painted pushrods, red painted brass manometers and gauges, even red nuts, handles and pipes. In spite of warnings the model builders, even kitmakers copy this which sometimes make the VIIC models look like they were an item of an amusementpark. Generally there is a tendency to overdue the weathering, corrosion, the wear and tear of a VIIC model both externally and gloomy internally. The lifetime of a WW2 VIIC was fairly short, don`t make your model like a heap of rust ready for the scrapyard.
Tore