The earliest literature in which it surfaces is the Olympic Catalogue, released in the autumn of 1982 for the 1983 model year. However, if you look at old pro race photos you'll see it on the 1982 team issue bicycles. It was common practice to test products with at least a season of pro racing before commercial release. So, depending on the exact nature of the frame, it should be no earlier than 1982-1983. . A 1983 model year would coincide with the apparent introduction of the cable housing trough. I would have expected Portacatena compatible dropouts but these look like they may have had some extra work done on them by the builder