Your reply suggests that individuals were promoted to SGT according to trng completion or deployment. Sorry, not true.
There is no branch in the US military that establishes rank based on any criteria other than a commander's decision to promote... although some commanders may establish review boards comprised of senior enlisted personnel to provide advice on whom to promote. Promotion to the Company Grade NCO (lowest level is SGT or E5) is usually based on merit, experience, leadership ability and foremost, command of job skills.
One stripe in the Army Air Corps is PVT (E2), not SGT. SGT in the AAF was three stripes.
No rank, officer or enlisted, is promoted based on overseas assignment.