Correct answer is... 590 kg. It is equal to 1300 lbs. Empty weight of Stinson 108 is total weight of the airframe, engine, avionics and all other systems installed by manufacturer.
The biggest civil aircraft has empty weight of 250,000 kg (628,000 lb), so Stinson 108 has 0% percent of it's weight. Typical jet airliner has about 39,500 kg (87,100 lb), so in the comparision Stinson 108 has 1% of aircrafts like B737 or A320.
Disclaimer: Our articles and data connected to empty weight of Stinson 108 are based on public data from various sources. We are very picky to select an reliable data providers, but we cannot guarantee that everything is 100% error-proof. We recommend for any serious purpose - as a rule of thumb - to request offical data about empty weight from manufacturer of Stinson 108.