The Clock System of the FR devices does not provide internal capacitors for the LF crystal, unlike the other MSP families do. So yes, if you want to use the crystal, you have to add them. I agree that more information should be there, as you can’t know which crystal is delivered and therefore which caps you’ll need.
However, if you don’t need the crystal, you can use these two pins as GPIO. That’s why the crystal and the caps are not populated by default.
If they were, it would prohibit the GPIO use of these pins.
If the pins are connected to a breakout header, you need to sewer this connection when using the crystal (parasitic capacitance and antenna). Usually, in this case there are 0Ohm resistors soldered on the EXP boards that can be removed.