That is big difference.
Dry shipping weight is different from the empty shown in the brochure, usually by about 400-500 lbs., depending on options. But that is still a big difference. It is possible that the 2nd weight you are looking at includes full tanks, but that is speculation. The best way to tell your cargo carrying capacity is to actually weigh your trailer, the subtract that from your GVWR.
Chap , DW Joy, and Fur Baby Sango
2006 Ford F150 Super Cab 4x4
2008 Surveyor 263