Yes - you should be fine - this is exactly how we use the TRF79xx devices with higher end MSP430s (like MSP430F5xx / MSP430F6xx, LM4F and the Sitara A8/A9 cores) as most of them have internal DCOs (running at higher frequencies, like you have) which can be leveraged.
The reason we show using the SYS_CLK output to the MCU on the reference design is hopefully obvious that we can add some value by this feature being available, and possibly reducing someones BOM cost.