Relax, your watch is as genuine as it gets. Just enjoy it. Wash hand is perfectly safe lah, no worries.
Both are chronographs with ROC being the chronograph version of the RO whereas ROO is a different line altogether.
Although both are chronos, ROOs are more aggressive in their styling and aesthetics. They are usually if not always thicker. A ROC is thinner and more elegant in terms of styling.
To differentiate, a ROC has its subdials at 3, 6, 9 position while ROOs have theirs at 6, 9, 12. There are other differences, like water resistance, etc. I'll leave it to you to explore.
Actually you may want to visit a boutique/AD to try on and see which fits better. Even at 42mm a ROO still wears quite large due to its integrated lug/thickness/heft.
ROC
ROO