There's another thread that I argued that SS was the model and RS was the option, therefore SS/RS should be correct (not that I am any authority on the subject). Another Gentleman corrected me stating his Father used to sell them and ALWAYS referred to them as RS/SS.
Well I was just watching some Camaro.org YouTube videos before bed (as you do), and watched the "1968 Chevrolet Communication kit, Sept 1967".
Here's a still from the video that may clear the debate up once and for all.
Note the 4 models...Base | RS | SS | RS/SS
Thats funny I have some original Camaro ordering info that lists the cars as SSRS.. I guess even the general didnt know what to call them. lol..