“No T shirts, no jeans, no shorts.”
I went all through High School wearing nothing but jeans and many times T shirts. (Of course that was in Texas in the early 60’s)
I’ll bet that your jeans did not have the knees out and holes in the butt. And you always wore a belt. (I sent my kids to school in TX in the 70s and I remember the dress codes.)
I’m from CA and the boys wore kahkis, cords, etc. to school in the ‘50s. T shirts with slogans would never have been allowed — too disruptive. Before we moved to TX, my boys wore pants that were made out of sort of a sail cloth fabric and kahkis — no jeans. That was in the early ‘70s.
I remember the pants specifically because my son suffered a broken leg and was in a cast. I had to rip out the side seam of his pants and install a hip to ankle zipper in all of his pants for the duration of the cast.