The kit must be installed on the appliance during the build. The LED kit is not a retrofit option as the connection for the kit is behind the unit, which will typically be inaccessible once the appliance is installed.
The EL fires can only be used with the Rinnai LED lighting kit. Other LED kits must not be used as they can damage the appliance and invalidate the warranty.
For more information refer EL electric fire LED light kit page extracted from the operation and installation guide.