LP-EM-CC1312PSIP:Support for Both 868 MHz and 915 MHz Radio Frequencies

Yes

The FCC certification is only valid for 915 MHz ISM band but the SIP can still be used for 868 MHz.

Just use the the external LC filter whilst operating at 20 dBm 869 MHz. This LC filter is included on the LaunchPad design for customers requiring operation at 20 dBm at 869 MHz.