I agree on the general seisan pattern they all have.
Within my experience, the shitei seisan (JKF-WKF approved version for competition) is the Jundokan version with standardised stances and kick.(shiko dachi, mae geri). The older version I was thaught has different perspective like seisan dachi with fumikomi geri (footstomp kick) or heelkick into the inner thy or loin (in place of standard mae geri). Yet I do not exactly know where these differences come from. When I ask about them I get explained 'koryu', old way.