While both the KTM 390 Duke and the KTM RC share similar engines and components, including the TFT display, it is not possible to directly fit the 390 Duke's TFT display onto the KTM RC without modifications.
The KTM 390 Duke and the KTM RC have different chassis designs, bodywork, and instrument panel mountings. The TFT display on the 390 Duke is integrated into the design of the bike and is not compatible with the mounting points and wiring configuration of the KTM RC.
If you are interested in upgrading the instrument panel of your KTM RC, it is recommended to explore options specifically designed for your model. KTM or third-party manufacturers might offer aftermarket instrument panels or display upgrades specifically tailored for the KTM RC series.
Before making any modifications, it's advisable to consult with a reputable motorcycle technician or authorized KTM service center to ensure compatibility and proper installation. They will be able to provide you with expert guidance on available options and potential modifications for your specific model.