If I change in Rhino -> Preferences -> language to english (I come from Germany :o) and my Mac localization is “german”.
After that, all items in the (Main)-Apple-Menü () are also in english. I think this can get problems with Apple (if you want to sell Rhino with the AppStore).
The items in the Apple menu are not localized, but the (accidental) behavior you describe seems correct to me. You set the language to English and everything is in English. We have no plans to use the Mac App Store, so it is not important if this is not the right behavior according to Mac App Store rules.