Are you aware the URL for the parts and schematics changed about a year ago? The old version of the files only worked on Internet Explorer and with the new version you get the same files BUT they work on everything EXCEPT Internet Explorer.
As to the serial numbers. you need to know if your serial number has a "1" or a "2" after the 6th position as that makes a difference in mid-year changes. But I've never had any luck entering the entire serial number, etc in the boxes top right that suggests that you can do that.
With year, model, floorplan ID and serial number 1 or 2 designations you get access to everything. No full serial number or paint colors needed.
Click this URL https://www.winnebago.com/owners/owner-tools
and then scroll down to Research Genuine Parts List to find all the parts listing and 3d drawings. However, tTo find the wiring, plumbing, etc diagrams click on the above link and then "Motorhome Knowledge Base" and then scroll down to those diagram links.