The first sentence of the last Cindigo build says:
There still isn't an integrated version for Indigo RT yet, but the export functionality works as before.
At the moment you need to export your scene "the old way" and render it directly with RT... :/
But with a promise for better integration with Indigo RT
Where exactly did you get that promise from? ^^
I'm sure Glare is already working on RT integration, at the moment Cindigo simply doesn't "see" your RT license and uses only a "indigo_sdk.dll"...
Also, is having C4D still think it sees Indigo Renderer solely a cosmetic issue, or could it possibly interfere with how the exported .igs file is built? I'm having render difficulties with RT that I didn't have with Renderer, like crashing the video driver and freezing my system. It looks like it's either temperature or something wonky with the .igs file that's causing it. But the same render earlier today with the Renderer trial didn't misbehave at all.
Indigo RT is a "crippled" version of Indigo with deactivated features. It works besides that 100% the same and gets compiled out of the same code and works with the same kind of igs!
But if you use features out of cindigo like sss and export to RT, the program should correctly explain that it doesn't support that feature...
P.S. If you decide to upgrade to Indigo Renderer from the RT version you only pay the difference left afaik