score:17
The laws in the US are state specific; some states require 'federally approved', others require 'according to technical standards'. So it depends on where you are going.
You can check for each state for example under this link: https://saferide4kids.com/car-seat-laws-by-state/
Note that realistically nobody will stop you and investigate your child seat's approval marks. At the end this is between you and your consciousness about your child's security.