I don't think either of those Schwinn's as being worth anything other than in the eyes of their beholder. The Super Le Tour was a 26 pound bike in their Recreational line up of bikes that were made in mass quantities for the masses that just wanted a bike with a cool sounding name and knew nothing else about bikes. The Prelude wasn't made in '84 AFAIK. But it's not something noteworthy either still likely a 24 pound bike.
Don't get me wrong, I rode a 46 pound Schwinn Varsity for over 35 years and it was a nice riding bike. But my attachment to that bike didn't make it worth spending money on.