Will it show up on a pre employment hair follicle test that I take more Norco (hydrocodone and acetaminophen) than prescribed?

Maybe. Often these test just report a drug is present or not. There are some companies that will quantitate and report the amount of drug in the hair which may suggest that someone takes more drugs than prescribed.
It shows if you. took the drug not the exact amount' But you should never take more of a medication than directed by a doctor.If you are taking more of a narcotic like norco (hydrocodone and acetaminophen) you may have an addiction problem.