SinoSoldier
Colonel
I was under the impression that although both F-15SK and F-15SG were based upon the F-15E airframe, they were designed with airsuperiority in mind since they are the mainstay fighters for their respective nations. Other aircraft that entered the South Korean competition were the Su-35 and Eurofighter Typhoon. I think this is indicative of what South Korea was looking for.
They are designed with the secondary option of engaging in air to air combat. This simply means that they are able to fire guided air to air missiles and have some form of airborne radar.