The 1981 Koga-Miyata FullPro-L had the full Dura-Ace AX group including the aero-levers. I would think Shimano introduced them already late 1980 than.
I have a PEKA, circa 1981/82, with modified Nuovo Record levers. I have been told that the builder (Peter Serier) wrote off 3 bars before he were happy with the result. Cables run internally through the bars too.