Bought a 5R barreled action from a member here a few months ago and it wasn't marked 5R. Clearly had 5 lands but I was still concerned so emailed serial # to Remington and got quick response that it was a 5R. So unless the bbl had been changed (don't think so) at least some of them were not marked 5R. It's an S prefix 24" unthreaded barrel but then another 20" threaded S prefix barrel I have is marked 5R.