I would be more concerned with cheap chrome parts sealing properly. As far as black parts retaining heat this is not true either. If they are exposed to sunlight or other artificial light they will absorb more heat that light colored parts.
As far as the type of metal they are made from some metals will conduct heat a lot better than others and this will change the thermal properties of the engine. Aluminum and copper will dissipate heat a lot faster than steel or cast iron.
Artificial Intelligence is no match for Natural Stupidity