If a person wants to know if someone's pubic hair is the same color (or in some cases, same style) as the hair on their head, they might ask "Do the drapes match the carpet?" The drapes are hair; carpet is pubic hair. This is akin to asking "Is she a true blond?" Someone's obviously dyed hair might prompt this speculation: "I'll bet the drapes don't match the carpet."
Lisa has a shaved head. I wonder if the drapes match the carpet?
Didn't she used to be a brunette and now she's a blond? I'll bet the drapes don't match the carpet.