I think Dura-Ace was available with SIS in 1985. I don't know when the first Shimano freehub/cassette was available but its introduction predates SIS (and for a while both freewheel and cassette hubs were offered up until Hyperglide was introduced). My roadie bought in 1986 is 6-speed SIS Uniglide freewheel. I think Hyperglide was 1989. My MTB from 1988 is 6-speed SIS Uniglide freehub.