No.  There are no dual-frequency RU/GF sets.

There are indeed dual-band RU coil sets, but in every case except two, one band is a communications band and the other is a navigation band.  Examples:

CBY-47076     400 to   600 kHz for MF reception or homing

                      3000 to 4525 kHz for GF-* comm. transmitter

CBY-47107    540 to    830 kHz for ZB-* VHF homing adapter output

                      3000 to 4525 kHz for GF-* comm. transmitter

There is NO capability for swapping from one communication frequency to another by simply selecting the alternate band of a dual-band coil set.

There are NO dual-band GF-* transmitter coil sets, nor any RU/GF set with more than one transmitter or receiver.  (RU-4, -5, -6, -10, -11, -12, -18, -19 liaison receivers included one or two receivers, but never include a GF-* transmitter.  Those RU models were used with GO-* and GP-* liaison transmitters.)

The only way to cover two channels with an RU/GF set is to have two complete and separate RU/GF installations...which would have been extraordinary if ever it occurred.  That was a significate advance provided by the ARA/ATA, SCR-274-N, and AN/ARC-5 command sets.  Two transmitters in the transmitter rack provided two switch-selectable channels for transmit, and two of the three receivers in the receiver rack provided simulateous reception of those two channels.

Mike / KK5F