This Fits Your 1991 GMC C3500 Sierra SLE Extended Cab Pickup 5.7L Chevrolet V8 A/T
Full size assembly image of PICK UP BOX. BOX ASSEMBLY. FLOOR. FRONT & SIDE PANELS. (1/1)

PICK UP BOX. BOX ASSEMBLY. FLOOR. FRONT & SIDE PANELS.

6. 5 foot stepside. Lower. Rear.