The Gran Sport, sold from about 1968-1976, was a 531 throughout / almost throughout bike, 23-24 lbs, with peugeot PX-10 components. A GREAT bike, very under-rated. Worth at least $200 in good condition.
The asian gran sports unfortunately were like raleigh gran prix. No effort spared to make it cheap. 2030 carbon steel gaspipe frame, bottom-of-the-line suntour gears (work well but are heavy), and usually top it off with an ugly crankset. sorry but your bike is probably worth $50 tops, it probably weighs 27-29 lbs.