I really like that color also. All it is is bees wax on the plain veg tanned tooling leather. I melt the bees wax and apply it to the holster with a tooth brush and then use a hair drier on the holster to keep the wax liquid until it soaks into the leather. Very simple.
I just watched this guy (I could not understand a word but I got the point). Be careful though, bee wax if flammable.
http://www.youtube.com/watch?v=9veen5Nh5uc