Really?
I was National Honor Society...I didn’t know there was regalia for me to wear.
I did not get a regalia too but that was back in the mid 80s.
It probably varies. Back when I was a youngster, we got gold cords that we wore over our shoulders. These days, most chapters offer either gold cords or a collar or stole worn over the graduation gown.
Don't mean to disparage the wearing of honors stoles, but my daughter just graduated college with a BS in Aerospace magna cum laude with honors and for the two she had a couple special cords to wear around her neck, over her robe and notations on her diploma ... no stole like the Masters and PhD graduates.
Did this practice begin around the same time schools started holding graduation ceremonies for elementary and middle school kids, and teams began awarding participation trophies? That might put it into perspective.