I'm confused. I thought the Liner always got the insignia or decal before the steel pot did. That way you could display the bright, colorful insignia in a parade and when you went into combat you could cover it with the Pot. For most helmets, they were only marked with an officer's insignia. And it seems that the higher ranking officers, Colonels and Generals such as Patton, would mount their rank pin on the front of their pot.
Veterans---please explain. Are you referring to only the 36th Division's policy? I know I've seen lots of Texas boys with their patch painted on the steel pot. And if you believe the movie "To Hell And Back", it seems that the 3rd Division painted an insignia on both sides of the helmet. Maybe that is only Hollywood. But for general application, I've seen more liners with insignias. I think that was true even in Viet Nam days.
Steve