OP, you need to provide pictures. Good overall left and right sides, pinky tables, closer up both sides of neck. From what I can tell, this is probably a "King Cleveland" their student line, but branded for a music store or distributor. "Pads and keys fully functional" is not meaningful unless you are an experienced saxophonist with a leak light and you tell us it'll play all the way down to a pianissimo low Bb. And even then, taking it out and starting to play it after decades of resting, is almost certain to cause things to swell and shrink and create leaks, plus 50-80 year old cement holding corks and felts on is likely to be brittle and fail after some use. The assumption on a horn like this is that you'll need to replace some or all the soft materials before it's a reliable instrument.
If as suspected this is a stencil of a student instrument, market value is quite low. If it currently plays down to low Bb, and the finish is good and clean, and no dents or bent pieces, maybe $200-300. If there's leaks, lower than that.