The answer is: "Nobody knows". So called "Dry" weights are at best a joke and mostly useless - except to salesmen who LOVE to quote them. :S There is little if any consistency from one manufacturer to the next as to what is included in their published "Dry weight". Some count AC, awnings, upgraded appliances and some do not, you never really know just how they reached that number.
For a really belly laugh look at the "Dry Tongue Weights". Again no industry standards as to what constitutes a proper (safe), tongue weight. Some will compute based upon 10% or less of an already ridiculously low dry weigh when 13% is considered by most to be about right.
IMHO: Anyone who quotes you dry weights of any kind is NOT your friend. Subtract the CCC from GVWR and you will be close to the trailers actual dry weight but remember that no one tows an empty trailer and most folks load far more weight than they think. A trip to the scales, which of course only comes after you buy, will confirm just where you stand but on any trailer between 20' to 30' most folks can expect to load at least 1000# to 1500# depending on how and where you travel.
Don't forget to include the weight of your tanks. Lots of us travel with less than full fresh tanks and we usually are headed out with empty grey and black but.... You can easily find yourself with full grey and black when it is time to head home if the dump station is out of order or the line necessitates more of a wait then you choose to deal with.
Never buy any rig that does not have substantial CCC, you will need it and any well built rig will have it. I have yet to ever hear of someone who weighed their rig and found it was less than they thought. :B
