Dry weights are a marketing tool for suckers. No trailer ever weighed it's dry weight, even at the factory. Doesn't include battery, any options, water, etc. Batteries and LP gas tanks are added by the dealers at their lot.
From a recent Forest River brochure (UVW = dry weight):
UVW (Unloaded Vehicle Weight)* - is the typical weight of the unit as manufactured at the
factory. It includes all weight at the unit’s axle(s) and tongue or pin and LP Gas. The UVW does not
include cargo, fresh potable water, additional optional equipment or dealer installed accessories.
*Estimated average based on standard build optional equipment.
Here's Jayco's definition (July 201
Unloaded Vehicle Weight (UVW): Sometimes referred to as “Dry Weight,”
UVW means the typical weight of this trailer as built at the factory. The UVW,
as used in product literature and other promotional materials, does not include
cargo, fresh water, propane, options or dealer-installed accessories.
Note that Forest River includes the LP gas weight but Jayco does not. A single 20 lb propane tank weights about 37 lb full. I'm guessing you've got two. 30 lb tanks weigh about 50 lbs. Batteries run around 40-50 bs or more depending on size.