Just chiming in with some actual measurements, for the sake of posterity (this is still the #1 result on Google if you search for "true scale vintage collection x-wing").
The toy itself measures 19.55 inches (49.66 centimeters) in length, measured from the tip of the nose to the end of the engines. The X-Wing is canonically 43.96 feet (13.40 meters) in length: