I think I found the same bike intact at a garage sale last weekend. The stickers were "magnum 37" its got the same weird underside mounted rear drop outs. I believe its one of MCS's first attempts to compete with free style bike makers. I'm pretty sure its 86-87 because it only has back pegs, and no front brake or pegs. It has all the equipment that it was built with-
Sun tour bear traps
GT crank, chain, and back pegs only.
Robinson handle bars
Dia Comp MX brakes
Skyway 5 spoke graphite rims.