UVW on the sticker is SUPPOSED to be the total weight as weighed on the way out the factory door but I don't think they always do it, despite any regulations. Which gov't. authority would ever check the weights? What about options and even tires?
I weighed our new TT at a scale on the way home from the dealer and after factoring in the propane tanks and battery and draining out all the water that was in the FW tank, it was 190 lbs more than the weight on the UVW sticker inside. The only thing that makes sense is that the additional weight is from all the options we ordered and that they did NOT weigh it on the way out of their factory.
The sticker on the exterior on the front street side is often (always?) the generic brochure weights. That's the case with our TT. Not only that, the sticker showed tire data for standard LRC tires despite ours coming with their optional LRD tires. I could see someone inflating their LRD tires to the 50 psi on the sticker which would eventually lead to a blowout. Would they actually have a stock of the exterior stickers for every combination of options? The GVWR on our exterior sticker does NOT match what our TT actually is by a LOT. Are these stickers covered by regulations?
I'm pretty sure the UVW is always on a sticker inside a TT, either on the entry door or inside a cabinet. I wonder how often manufacturers just use the factory listed dry weight on the stickers. I've read some people claim that the UVW on a sticker doesn't include things you'd expect them to like microwave, spare tire and upgrade to a power awning.
To add to the OP's question, I would not trust the NCC/CCC figures listed by a manufacturer. I also weighed our TT fully loaded up for camping plus the weight of mods and the additional wt. of everything on top of the factory listed UVW which came to only 864 lbs. Factory listed NCC was 1563 lbs which should have left 699 lbs under the GVWR, however the scale showed we were just 200 lbs away from the GVWR. A full tank of FW would put us over the GVWR.
You cannot trust any factory weights except for the GVWR. It would be a really good idea to take a new TT to a scale for your records in case there is ever a problem with the frame, axles or tires as well as knowing how much capacity you have for cargo and mods/upgrades. They will often immediately blame an owner for overloading. It would be an interesting exercise at an RV show to look at the weights on inside stickers and compare them to the factory listed wts.