Hello David,
Yes, exactly. K60F120M is not supported right now and actually I don´t see support in plan for KSDK 1.3
All supported MCU you see in Release Note or some information are also at ARM Cortex-M4 Cores|Kinetis K MCUs|Freescale

For other cases (unsupported/custom chip), you can modify it according to yourself.
I´m attaching the guide.
I hope it helps you.
Best Regards,
Iva