My guess for shifting>
1985 (Shimano 600 6200 Series) Pre SIS Both Friction, 6 Speed Freewheel
1986 (Shimano 600 6200 Series New SIS ) SIS introduced Rear only, Friction Front, 6 Speed Freewheel
1987
Master: (Shimano 600 6200 Series New SIS ) SIS introduced Rear only, Friction Front, 6 Speed Freewheel
Expert: (Shimano 105 1050 Series SIS) SIS Rear only, Friction Front, 6 Speed Freewheel
1988
Master: (Shimano 600 6400 Series SIS Introduction of 7 Speed ) SIS Rear only, Friction Front, 7 Speed Cassette
Expert: Expert: (Shimano 105 1050 Series SIS) SIS Rear only, Friction Front, 6 Speed Freewheel (?)
1989
Master: (Shimano 600 6400 Series SIS Introduction of 7 Speed ) SIS Rear only, Friction Front, 7 Speed Cassette
Expert: Expert: (Suntour GPX Accushift 7 Speed) Accushift Rear only, Friction Front, 7 Speed Freewheel (?)