To take (or not take) SAT subject tests?

My son is a junior. He is planning on applying to UNC Chapel Hill, NC State, UVA, USC, and Clemson. He has taken the SAT and has a 1300 superscore. Should he plan on taking any SAT subject tests?

SAT subject tests are optional for USC.

Also, his plan could be changed at the time he applies to colleges.

You may want to google: which colleges require sat subject tests

Thanks. That’s USC as in South Carolina. I don’t think they require but wasn’t sure about their Honors College recommendations. Looks like UVA says strongly recommend, which in my mind says he’d better take them.