A few years ago it was. In the 90s the Air Force got rid of the buck Sgt (E-4) rand and made it Senior Airman, a Non-NCO grade. Now, only the Marines recognizes an E-4 as an NCO.
Corporals[E-4] in the Army are also NCOS, just a junior NCO.
Try not following a order from a tabbed corporal. Talk about a bad day :)
The army doesn’t regard a Corporal as an NCO, or the Navy a Petty Officer 3rd Class?
At that time, E-4 was both ranks Buck Sgt and SA. They just did away with the NCO side. I promoted from SA. to buck and all it meant was the star in my chevron turned blue and I had to take those NCO leadership courses. :(