This order of battle could not have been constructed without the aid and knowledge of Keith Rowe and Dan Allmacher, who quite literally have the best informed presentation on the ROK's Order of Battle, outside a government.
AsianDefense Group @ Yahoo Groups -- This site has quite a bit of discussion regarding Korea including the writings and documents of Keith Rowe and Dan Allmacher
Korea Insititute of Military History. The Korean War, vol 1. (Lincoln: University of Nebraska; 2000): p. 71, 83
23rd Infantry Regiment
The 23rd Infantry Regiment was activated on April 20, 1949 at Masan and was first commanded by Lt. Col. Kim Jong P'yong. The unit was initially assigned to the 3rd Division when that unit was activated in May 1949.