In addition to what was stated above about the "in-house" Winnie fabrication - I was impressed with how the drawings, schematics, parts lists are all available to the owner from winnebagoind.com/references. The manufacturer or our prior RV felt those were proprietary and would not release them to anyone except a Dealer. Every Winnie cabinet part, pillow, wire has a part number printed on it. I can enter my serial number and print a 70 page parts list specific to my coach build as ordered.
Here is an example of their 3D drawing platform available online:
