>>5021330
Unlike many large mammals, all dinosaurs likely saw more colors than even we do. Both crocodiles and birds see in color, and so do other reptiles, so dinosaurs definitely did see in color.
>>5021368
As long as it can catch prey and live on to breed, a trait will be passed along even if it doesn't harm or help.
Predator colors can vary broadly just as long as it doesn't hinder their success. (Tigers get away with that color since their prey sees it as green)

Komodo dragons also have faint but colorful iridescence.