In a perfect world the plated tare would include the bolted on accessories whether they be tent poles, fridge, spare etc for a camper, or the bullbar, roof rack, etc for a 4by.
But the plated tare can be just the bare basics (ie bare box trailer in the case of a basic camper) without tent, spare etc.
I think a lot of the cheaper manufacturers (as has been mentioned on here numerous times) record the lightest tare they can get away with ie 500kg then give the trailer an ATM of 750kg so they can get away without fitting brakes.
Pity the poor customer who purchases one of these and find they have reached the ATM with the supplied bolt ons (tent etc) as they drive out of the suppliers yard, even before adding personal effects, water, fridge etc.
Peter H