The following information was provided to the Federal Aviation Administration by the Cessna Aircraft Company. The flight crew accepted the newly purchased airplane at the Independence Municipal Airport, Independence, Kansas, which departed from there on a ferry flight to Croatia. During cruise, a low fuel pressure annunciation was observed. A visual inspection with the airplane's wing inspection lights was conducted; the airplane's left wing upper skin was compressed aft of the center spar and forward of the aft spar. The flight was diverted to Allegheny County Airport, Pittsburgh, Pennsylvania, which it landed without an incident. Upon a ground inspection of the left wing, the left wing's fuel vent had been covered with a temporary vinyl applique used to cover the permanently painted Croatian registration numbers during the ferrying of the aircraft. The vinyl was to remain on the wings until the aircraft reached its destination where the Croatian registration would be revealed. The airplane's preflight checklist, exterior inspection, step 6, right wing, item "h" and step 11, left wing, item "C", both state "Fuel Tank Vent ---------Clear".