* The Vehicle's Door Jamb Sticker (or its equivalent): This sticker will have the GVWR clearly printed on it.
* The Owner's Manual: The owner's manual for that specific truck will list the GVWR.
* The Vehicle's Title: Sometimes the GVWR is listed on the title, though this is less common.
Without knowing the specific configuration of the truck, it's impossible to give you a precise GVWR.