I had a nehru style shirt back in the 70's, and living in Amish country I see the basic same as nehru jackets all the time - they call them straight cuts around here, and many of the local congregations require them.
About the shirt buttons - in my HS days (Oklahoma, in the early 70's) the dress code required all but the top button to be closed, and belts if there were belt loops on your pants. Come to think of it, some guys did try to pull their shirt collars back a bit like that, but it was so that their hair wouldn't hang over their collar in the back, because the hair code said no hair on the collar in the back, over the ears on the sides, or below the eyebrows in the front. And yes, that was public school.