This is the 3rd version of this cover. Versions 1 and 2 can be seen in an article in Savage Sword of Conan (Marvel, 1977 series) #41.
Colors: “George Roussos enhanced the [cover’s] mood with his coloring.” Roy Thomas, Barbarian Life: A Literary Biography of Conan the Barbarian Vol. Two, (n.p.: Pulp Hero Press), 276.,
Includes a special note from Roy Thomas on producing one hundred issues of Conan. Letters from Bobby Cameron and Gary Norman.