I don't know if that's true or not, though some color words are definitely older than others, so I can imagine it. Do you have a source?

I'm reminded of how the word "orange" is relatively recent, and named after the fruit. Ever wonder why people with orange hair are called "redheads" even though their hair isn't technically red? From the links, "redhead" arose in the 1200s, while "orange" wasn't used to describe color under the 1500s. So "red" was the closest color descriptor at the time "redhead" was coined.