SawTroll
Information Collector
The 670 went through several small changes in it's run. The 4 basic versions are 670, 670 Super, and 670 SuperII and 670 Champ. The versions were never made at the same time and west coast versions of all were made. I'd say it ii safe to call your saw a 670 Super West Coast. It is also what I would call an early or white label Super because of the older style chain brake and white decal. Later Supers and Super II's have the newer style chainbrake and black decal.
A rough time line is (and sawtroll may disagree with the start date)
and this is off the top of my head:
670 1986-1987
670 Super 1988-1990
670 Super II 1991
670 Champ 1991-1997
I have no evidence that you are wrong, as very few Jonsered documents from before the late 1980s are availiable to me - I guess I could find more exact datings of the changes though, but you are close enough to how I remember it!
In case someone don't know, the "Champ" designation was a result of three consecutive wins in the WLC, 1987, 1989 and 1991.