The Specialist Ranks were a point of contention from their inception.
The differences were being hashed out, and ultimately decided in the early seventies. Specialist, as opposed to hard-stripe insignia was arbitrarily awarded, solely by the MOS you held when the rank was awarded. But even that was not always so! I was awarded the rank of Sp-5, while holding a slot of Senior Aircraft Armament mechanic, an E-6 Staff Sergeant slot, while simultaneously being the Production Control Supervisor for an Organizational maintenance unit, responsible for maintaining 27 helicopters. Later, when I attended another MOS school, Small Arms Repairman, the E-5 rank for that MOS was Sgt. So, I held both ranks at different times, Sgt and Spec-5.
In Army Aviation during my Vietnam-Era years, the Helicopter Technical Inspectors (TI) usually held the rank of Sp-5 or Sp-6. But we also had a TI that was a Staff Sergeant. Are you following this confusion? The Senior TI was a Spec-6, and at times he was the Platoon Sergeant. We had a younger Spec-5 that was promoted to E-6, and for whatever reason he was awarded Staff Sergeant rank. He immediately was placed as Platoon Sergeant, over the existing Spec-6 Platoon Sergeant. As an E-6, the Spec-6 TI had both more time, and time in grade than the newly promoted Staff Sergeant. The Spec-6 challenged this, and he won. The Army did decide that a Spec-6 with time in grade over a Staff Sergeant, outranked the Staff Sergeant. This decision is argued, misunderstood, and debated to this day.
Oh...And did I say I was also in the rotation of Sergeant of the Guard, and CQ, as a Spec-5?
So, I have 4 Honorable Discharges. One from the Regular Army, one from the Army Reserve, and two from the National Guard. One of them says I'm a Spec-5, the other three say I'm a Sergeant. Unfortunately, I already have a headstone in place in a National cemetery, atop my deceased minor daughter. And this headstone has my name as Sp-5, even though I was a Sergeant longer, and later, than I was a Spec-5.
None of it matters now, except there are Junior Corporals acting as supervisors over Senior Sp-4's. And tomorrow, that same Spec-4 could be transferred to a different slot, and then be a Corporal. The NCO training, while I was in was the same for the Specialist ranks as it was for the Sergeant ranks. Spec 5's and Sgt's went to the same NCO school. Further, during my time on any Post, any E-4 and above was allowed in any NCO Club, regardless of being a Specialist or a hard stripe.
The creation of the Specialist ranks created more problems than any problem it was supposed to overcome.
WAYNO.