No that is NOT sounding correct!! Given that a turbo DC-3 will have a lower APS weight due to the lighter engines, that statement is still way wide of the mark. Across seven DC-3's, our freighter config APS weights varied from 8138 to 8553kgs, (type of floor, totally stripped out or pax overhead racks left in etc etc), and if we assume the up-to-date MTOW of 12,200 kgs, this gave a useful load, after allowing for 90 mins fuel, (120 I.G.), of between 3261 and 3647 kgs.
So, 15-20 tons? Put it through the door and bust the aeroplane before it even turns a wheel, I would suggest.
Having said that, I once nearly took a max HP-7 Herald load out of Bournemouth; luckily the old girl told me in no uncertain terms that she was not going to fly like that even as we taxied out, or rather wallowed in the general direction of the holding point.
Throw all caution to the winds and yes, she will operate from 400-500 yard strips, but no accelerate/stop possibility, and an operating-speed/decision grey area as big as a battleship.
Nice guy maybe, but what grade of alcohol was he on?