No -- you'd have to outline the character and then flip it. But if you
keep it as an inline anchored object it will continue to flow with the
rest of the text.
I think I read somewhere that the forthcoming version of Illustrator
will have the ability to rotate individual characters within the text
stream without having to convert them to graphics.
Another solution may be Jongware's IndyFont (a script). It lets you
create a one-character font from any InDesign graphic. So you could flip
your R, create a font, and then type the character where you need.
I haven't tried IndyFont myself yet, so I don't know how it would all
work or come together.
IndyFont would be a really good solution for this. The free trial allows you to make a single character font. http://www.indiscripts.com/post/2012/06/indyfont-build-opentype-fonts-from-within-indesign