Why do you need to know the “dry weight”? It’s a kinda useless number since once purchased and brought home, the TT never used in the “dry weight” mode. However, I think that a very close approximation of the dry weight can be determined using information on the vehicle information sticker and the tire and loading information sticker. Subtract the “never exceed” cargo weight on the tire and loading information sticker from the GVWR weight on the vehicle info sticker and that should provide a reasonable estimate of the “dry weight”. I say estimate because there are differences in opinion as to what is considered cargo. I.E. is propane considered cargo? Is the battery considered cargo? The most important weight is the actual weight is that when the TT is loaded with everything one is expecting to use on the trip. That determination may require a trip to a local scale.