Isn't an 80SS a DOHC? Is that what you want? If so I don't think they bring much. And remember its not the milege as much as the overall age, when its over 10 years, it might as well be 100. All the rubber bits are hard, body pieces are brittle, the cables are corroded intenally, the wiring is all hard and corroded, the tires are likely too old (if over 6-8 years) the brake pads are hard and maybe glaxed, etc.
Garaging helps, at least the paint woon't be faded. But age is age. Unless the garage was temp controlled, it still went thru condensation cycles that muck up the fork oil, shock oil, engine oil. I certainly woldn't make payments on it. Buy something modern with borrowed money.