DURING LANDING ROLLOUT IN VFR CONDITIONS, A DC-3C, OPERATED BY A 14 CFR PART 135 OPERATOR, ON A 14 CFR PART 91 POSITIONING FLIGHT, NOSED DOWN ON THE RUNWAY SUBSTAINING MINOR DAMAGE. THE PIC, SIC, UNAUTHORIZED JUMPSEAT RIDER, AND TWO CARGO LOADERS LOCATED IN THE COCKPIT/FORWARD COMPARTMENT WERE NOT INJURED. NO CARGO, BALLAST, OR PASSENGER SEATS FOR THE CARGO LOADERS WERE LOCATED IN THE REAR OF THE AIRPLANE AT THE TIME OF THE INCIDENT.