If it were a stolen design, they'd be able to sue them
Kinda like when S&W (or was it Springfield arms?) copied the Glock and the almost all of the parts would change out on to either pistol. Glock surely won that case for copying.
My last Winchester muzzy came with a 24 page manual and a video. TC's manual is about 70 pages. And i even think they include a video too.
Im bettin 90% of people just pop the video in and sit on their butts and watch it rather than read the real manual.