Will a 1968 fleet side bed fit srep Chevy truck?

No, a 1968 Fleetside Chevy truck bed will not fit a later model Chevy S-10 (often referred to as an S-series or Sonoma/Hombre) truck. The S-10 is a much smaller, compact truck than the full-size trucks from 1968. The bed dimensions, mounting points, and overall frame size are completely different.