I'd like to see documentation for this claim. Prior to the unification, the various kwan all taught their own system with their own forms. Since these systems were derived from Shotokan, they were mostly taught using the pinan forms. Those forms were Okinawan-originated. None of the Korean form sets (palgwae, taegeuk, etc) existed until after the unification.
The Palgwae and Yudanja forms were introduced in 1969 (if memory serves - the late-60's at any rate). Koryo was different, and was replaced by the current version 3-4 years later. I believe these were the only two versions of Koryo. Neither existed prior to the unification. Like the palgwae and taegeuk poomsae, the yudanja forms were designed by a committee. It wouldn't be correct to say they were developed by the Kukkiwon, since the KKW didn't exist yet. It would be more accurate to say they were developed by the same people who eventually formed the KKW.