McGivers speculated that he was "probably a Sikh" before she even knew his name, just from looking at him sleeping in the chamber. How she figured that is anyone's guess, since he didn't have any visual indicators of Sikhism.
It's been debated, whether he had brown makeup for this role or not. I don't think there is any confirmation from behind-the-scenes notes or whatnot. Those more familiar with the ins and outs of film/TV production lean toward the viewpoint that his complexion seemed darker and differently-hued here than could be accounted for with a natural tan, considering how he appeared in some other roles as well as TV commercials from around this time going into the 1970s. As has been mentioned in other threads, although Montalban was born in Mexico, he was not of Mestizo origin; both of his parents emigrated from Spain. On a social level, he did face discrimination and marginalization in American show business as a "brown person," in his own words, since was from Mexico.
Kor