I know this is rare because I have not seen one advertised anywhere since starting the layout around four years ago. I have another RDG (yellow #2766) SW 1500 switcher that I purchased here in Australia about a year into the build, but have not seen any others since.
I checked the Athearn website and these where produced around 2009, and came in three road numbers. After doing a little research I found out that this switcher was originally all yellow and was involved in a wreck then rebuilt, during the rebuild it was repainted in the all green RDG scheme.
Photo credit to Author Kim Peirsol.