I don't know. It may have been something that varied depending on who masked off the curves when the locomotive was repainted. It could have changed from locomotive to locomotive or from era to era. Most photos I can find show the Kato revision to be somewhere in the middle. This F3 shows the yellow going way back and under the horn on the engineers side. And then this one shows it coming almost to a point. So I imagine you could just blunt the point on the old Kato paint scheme with some yellow and it would be correct.