If it were mine I would upgrade the red dot sight to something better. I have red dots on most of my range toys and especially shooting at an indoor range you don't have any problem seeing the sights all you have to do is put the red dot on the target gently pull the trigger and you are good to go.
If you want to go back to iron sights a Google search should turn up some sights. MidwayUsa has a lot of Ruger parts and Brownells has a lot of Ruger parts you could check them out. Might try Ruger out too they probably have sights for the tactical model.