I am trying to get more information on the original equipment of my Antares. I have found the 1982 catalog, but mine is equipped with a later Shimano SIS rear dérailleur, and a Shimano 600 EX Arabesque in the front. I'm curious if the bike was originally Arabesque? In 1982 they used Sun Tour BL. Would anyone know how many years the bike was produced? I know of 1982 and 1983.
It sounds like you have replacement derailleurs. Bridgestone went to model numbers in 1984 and that SIS rear derailleur would be at least a 1986. I can confirm that the 1983 Antares also used BL as OEM.
I suggest you start looking at component date codes. Refer to components page of the Vintage-Trek website. It will tell you the formast and how to decode them. If you can find a several components with date codes within the same year, it is generally safe to assume that componets are original and the bicycle is more than one model year newer than the date codes.