Unfortunately Lippert can build a frame to whatever secs are on the design page in front of them. Length, height requirements should be easy to build into anything and within those requirements they can probably design anything at several different price points. ONE thing they can't control is what the rv manufacturer bolts to it when they get their hands on it. Where the majority of the weight is distributed and how the house sits on the frame and is bolted to the frame. They still have to cover their end of the warranty to the best of their ability.
That being said, I'm sure there are several in the plant that have absolutely no formal training either. Welding isn't hard but a good welder is hard to come by.fusing the metal together is just a small part of the process. Knowing what works best to do that and what the perfect surrounding conditions need to be to get to where the conditions are perfect is what most novice welders don't understand.