The sales brochure was not meant to be gospel and I’d never pull it out if I were pulled over. That said, these day most speak of GCWR and it’s the only document that I’ve seen that list the GCWR’s based on your specific truck config."But the sales brochure said it was okay..." isn't gonna hold up in court.
Main point is that folks can make sure they’re under the tow capacity specified by the manufacturer and be safe in the road.