I rewatched the promos and yes, Tuuli is shown wearing Green. Misscoloring is a possibility. I have always considered that Metrutoran have less saturated colors than Mata colors (combining better with their gray limbs), so I think the colors should be different.
If it was misscolored, a Ga-Matoran should be Medium Blue (right) instead of Light Blue (left).
I have a theory that I explained here that Black isn’t a Ko-Matoran color.