If it is equipped as built, It would have to be late, as Juvela suggests, and I think likely '84. Shimano 105 didn't exist until 1982 and that odd grey finish is certainly a second or third iteration (maybe even later--105 got a reboot in '86) most likely the bike would have come with Shimano 105 clipped, semi-platform pedals. Look clipless pedals first came out in 1984 but didn't look like those, until about a year later after the ridiculously blocky first version sat unsold. (they remarketed the first ones as mtb pedals). I think the groupset will be your best bet for nailing down the year--that grey thing was one or two years --if memory serves me. (often not).