Just saw this thread.
I just worked with the owner of the Gatling that was on the episode of Pawn Stars.
We rented the gun for a movie project.
He confirmed it's completely scripted - in other words fake, as if there was any doubt.
The Gatling was not for sale, and did not sell, it was rented, the same way we rented it.
It's TV guys, entertainment, don't sweat it.
The owner on left, stuntman in middle, me on right.
Sorry to have shattered anyones illusions, lol.