You have to pay to get the RVIA standards, but I believe the RVIA specifies how weight information is provided. The labeling seems very similar from one manufacturer to another.
It seems there is no requirement to actually weigh the unit as built. Car and truck manufacturers don't do that either. Instead labels include the weight of a "standard" unit. Often the wet weight is also listed based on a full fresh water tank and full propane tanks, along with the standard batteries. Labels also include specs for the options included, but not the actual total.
Dealer added options are not included. In my case that was 2 solar panels and oversized AGM batteries. Hold down bracket systems are not included. User upgrades are not included. In my case the big two were a generator and an upgraded foam mattress that was much heavier than the original mattress.
"Personal" items are another major, major issue. Personal items can easily top a thousand or even two thousand pounds. Included would be drinks, food, kitchen and cooking gear, tools, extension cords, hobby gear, chairs, BBQ grill and fuel, clothing, bedding, towels, cosmetics, first aid kit, etc, etc.
So if the label says 2400# wet, then add the accessories/upgrades. Those can easily total another 500-1000 or more pounds. Plus personal items and the grand total can easily exceed 4400#. Those are close to the numbers for my TC, a 9.5 Northstar Igloo. Mine is 18 years old and weights have increased since then.
