Yep, far as my understanding goes the "red" is meant to be for the hot, young, breeding slaves (totally not a porn fantasy btw) while the older, unattractive women are given grey instead.

So it says a lot about everyone there when you see middle aged, ugly, fat or some combo of all garbed in red. They consider themselves the types that ultra rich and powerful men totally want to enslave to use as lust buckets.