As a rough guide this is when each model first appeared............
Tuff I (Unstamped) 1974
Tuff I (Stamped) 1977
Tuff II (Steel Hubs) 1979
Tuff II (Alloy Hubs) 1982
Tuff II (Rear Alloy Hub Front Plastic Looseball Hub) 1985
So for an 84 build if you want to be era correct I'd say alloy front and rear hubs - but with the alloy rear / plastic fronts coming only a year later you may want to save a few pennies and go that route