Ich glaube die erste Registrierung "The first in Synthetics" war irgendwann in den 90ern, so in der Mitte.
Das schreibt Amsoil dazu:
In 1972, the breakthrough came. AMSOIL 10W-40 Synthetic Motor Oil, the result of years of research and inspired by aerospace technology, became the first synthetic motor oil in the world to meet American Petroleum Institute service requirements.