For a complete bike in working order with good rubber, I'd say that's pretty fair. Not the bargain of the century, but if you go much lower than that you'd be expecting to replace tires, bar tape, repack hubs, etc. You could certainly do worse.
To be honest: I have kind of a thing for Japanese bikes of this era, so this might be clouding my judgment.
edit: Tange #1 really is great stuff. It might never be a race bike, but if you take care of it, it could outlast you.