If you get a long box with a king cab there are "structural changes" compared to other pickups... I live on an airport with people who both work for Boeing and fly for major airlines. This 737 MAX thing was a major screw up, but not in the way most people think. One of my neighbors gave me a complete run down of the changes made to the control system that caused the confusion that resulted in 3rd world pilots auguring them in on a couple of occasions and Boeing losing billions because of their appalling Public Relations. I would have no issues flying on a MAX these days.
You are right. Refer to post #18 and especially to the pdf document link at the bottom of the article. Basically the engines had to be re positioned to avoid make expensive changes to the fuselage which made the airplane potentially unstable. To counteract the instability they installed software called MCAS which brought with it its own set of problems. The updated design should not even have been called a 737. Boeing did so anyway to save airlines expensive retraining for their pilots.