In the United States, there is quite a lot of data showing that race is a predictor of wealth, education, and (for lack of a better term) ‘having your life fucked around with by the system’ (e.g. stop and frisk, POC being arrested more frequently for the same crimes with longer sentences, etc).
So, barring a fairly detailed analysis about where and how every individual grew up, yes. Skin color is a good indicator.
I see you slipped the word ‘always’ in there. This is silly. You can’t have indicators be ‘always’. The whole point of an indicator is that it’s not always. If something were always, it wouldn’t be an indicator.