UPD2824, swap the 10.240 reference crystal, will it work?

So I got this old TRC-465 out of storage and feel the need to mess up something. I know they made channel kits for these, like exp back in the day, and I am thinking these just switch the 10.240 crystal with something else for upper and lower channels. Is that it or were these kits like an external oscillator to inject new freq into the TX and RX. I am trying to figure out how these things mix frequencies. I am thinking maybe a push button dpdt switch beside or on top of the ref crystal...

UPD2824, swap the 10.240 reference crystal, will it work?