That would be a first. I've flown jump aircraft around the country, and I know for a fact that Kapowsin aircraft don't change out the door to reposition, nor is there any reason to do so or practical means to accomplish the change. I know one pilot there who threw his Harley in the back for each reposition. No seats to put back in. I've flown long distances to jump in various aircraft, which are permenantly confiured as jump airplanes, and have never had seats in them...not is there a requirement to have seats in them.
Jumpers may use the floor of the aircraft as a seat, with belts permenantly attached according to the jump configuration.
Most caravans use a roll-up plexiglas segmented door, which isn't replaced for cross country work.
If you have personal knowledge of the arrangements of this particular flight, then so be it, but a jump aircraft is not requred to be reconfigured to fly cross country or beyond 25 nm. Show me the regulation.