I was active 90-94. Sra and sgt were both in use, but no one was promoted to Sgt after 1991. Airmen basic through sra had subdued stars on their chevrons where all ncos had highlighted stars. Senior airmen would become a Sergeant after further quals, most folks that separated after four years at that time were Sgt. Nowadays most organizations have converted their forms to electronic and use the current rank structure, effectively dismissing the fact that there are thousands of veterans out there that were once NCOs

I enlisted in '92 and hit E-4 in '94 (I think) and I was a Senior Airman.
We did have a small number of E-4 Sergeants in the unit at that time and I recall being told it was because they had made rank before the switch.
It was a little bit of a sore spot for some of us as those guys were officially NCO's but the rest of us (the senior airmen) were not considered NCOs until we made E-5.

Feeling your pain, old buck sgt here too. 214 says Sgt. Everything else says SrA, lol