An ESC or servo doesn't care what the radio link between the transmitter and receiver is. It only responds to the output from the receiver, and that should be the same for both. In both cases the job of the receiver is to take signals coming from the transmitter and process them, winding up with the right signal appearing on the right set of output pins according to the generally accepted standard. Servos and ESCs are designed to respond to that signal, and they don't care where it came from.
Some modern fully digital outfits have the same signal output, but at a higher frame rate, which older plug-ins might not cope with.
Some newer gear might have enough built in "cleverness" to work with both or either, but might be fooled into giving unexpected outputs if the 27MHz radio picked up interference and output a spurious signal, which might create confusion.