USB 1.0 (Full-Speed) bandwidth speeds are up to 12Mbit/s. 12Mb/s equals 1.5MB/s.
USB 2.0 (High-Speed) bandwidth speeds are up to 280Mbit/s. 280Mb/s equals 35MB/s.
Connect a thumb drive or an external HDD to a USB port and test Read/Write speeds with ATTO benchmark software.
If your Read/Write speeds are greater than 1.5MB/s then you know it's a USB 2.0 port.
Repeat the test on all USB ports.