If you are talking about a new TT, the dry weight on the sticker is what it weighed going out the door. Dry. That's the law now, for the U.S. DOT, And I can't imagine CSA and MoT being any more lax on this.
If you are talking about numbers in a sales brochure, it is often a guess, because these materials are published in many cases before any examples or even show prototypes are produced. Since there are almost always options, and only one number, it is usually weight without options. A few of the more upfront manufacturers will also list weight estimates for each option, so you can add these up yourself.
Beware of mandatory "option packages" because for many years the reasons for these was to permit the advertising material to show a lower weight and lower suggested price, even though no examples would be produced with that weight and price.
Even with actual weight measurements, you could be somewhat away from a useful number, for manufacturers that ship without LPG bottles, batteries, spare tires, etc. I know some dealers who order without A/C and install their own, but more often on PUPs than TTs.
