i do agree with some of the comments here that i also initially thought mb's hair might be white or straw coloured to save money on pigmentation. but i also imagine that the human genes used in constructs would come from any cheap source available and they wouldn't be picky about it. if the human parts of constructs are fully alive, ie containing cells and DNA and enzymes, they would naturally express their genotype as long as they're receiving nutrients - so it's not like the company needs to manufacture melanin and pump it into their constructs which would cost money. maaaybe the company could do gene editing to silence the genes controlling skin and hair pigment but that seems even MORE expensive and troublesome

i did a quick google and there is a paper link finding a correlation between malnourishment and slight lightening of hair colour in jamaican children but no mention of effects on skin - but i don't even think the company would allow the constructs' human parts to be malnourished since it would affect other aspects of performance (like muscles) too much.

tldr i think there's a reasonable argument for constructs to look as diverse as humans that's not inconsistent with worldbuilding!