Those are XR3-RED, most "commonly" found on New Model Blackhawk, SingleSix, however not allways and can be found on short barrel Super Blackhawks & Old Army, got you confused yet? :roll:
Equal spacing on the medallion front/top, slightly curved/flair backstrap, new model silver screw & escutcheon = XR3-RED
Here is some required reading,,,, quiz @ 5pm :wink:
http://www.rugerforum.com/phpBB3/viewtopic.php?f=3&t=131343