The 750 lb
weight is probably for the empty and dry trailer (and maybe only the
axle, and it probably isn't that
light anyway...). The 1700 lb posted on a 13' Boler is likely the Gross Vehicle
Weight Rating (GVWR), or the maximum which the trailer is allowed to be including optional equipment,
propane, water (if it has a freshwater tank) and cargo.
Actual ready-to-go trailer weights vary wildly. There might be some good info available from previous discussions - I'd try a Search.
I would supply my Boler's weight, but it's a 17' so it is not relevant here.