Originally Posted by
T-Mar
Regarding components, the crankset looks era appropriate. The Shimano Z-series front derailluer was available during 1986-1987 and the rear Light Action derailleur appears to be a verison introduced in 1987. However, the derailleur appears to SIS compatible while the shift levers appear to be friction, so the rear derailleur may be a replacement. The brakes appear to be later Exage models and may not be OEM. I'd focus on the front derailleur and crankarms for date codes that may provide a clue to narrow down the model year.
I was not able to see any codes on the FD, on account of it being really dirty, but I was able to see the code on the non-drive side crank arm (86C, presumably 1986 MAR) and easily access the codes on the brakes which are model BR-AT50 with date code KB27, which indicates that they were manufactured on 1986 FEB 27, which makes me think that they were probably original equipment for a 1986 or 1987 model. I will check on the FD when I can.