Thanks for letting me know on the link, my mistake. I searched the page and could not find it, I was able to this time.
I have an encoder set to "EGT_Ref_Set_1". In the stock Laminar 172, it moves the EGT ref needle; the dataref that changes is "laminar/c172/knob_EGT".
In the REP 172, the "laminar/c172/knob_EGT" still gets changed by the encoder, but it does not actually move the needle in the airplane. The dataref that moves the needle is "simcoders/rep/cockpit2/gauges/indicators/engine_0_egt_ref_needle" and that is not changed by the encoder.