I was just in Ireland, spent 10 days in and around Dublin and can say that yes RR is pretty authentic. It is an upscale pub pretty close to 2 that I visited in Dublin. The main difference is it is much more open, the pubs tend to make the best use of space and are more cramped because of it. The food looks like what we saw in the better restaurants in Dublin with typical pub food mixed in. I took the Guinness factory tour and pouring school while there and we were told that the only two places on earth you can get the beer made in the Dublin brewery is Ireland and WDW in Florida so that is authentic too.
Drew