Yes, as of version 3.6.1, you can create RTL layouts.
The text is automatically recognized as right-to-left based on the language applied to the text frame(s).
(This has been supported for several versions of in5).
The page navigation is based on the binding setting in InDesign (required the ME installation of InDesign).
in5 automatically detects this upon export and arranges the navigation buttons and page peels (when using the PageFlip with Page Peel Page Format).