I believe that Donald is talking about the colors appearing on the physical strip of film. With color negative film, the colors would be inverted on the strip of film, as it is negative film. On slide film, the colors would be correct.

The LEDs, if photographed, will be of the correct color (obviously accounting for the slight inaccuracies that occur with all color films) on the print. Whatever color you see will be close to what will be on the print.