
Philip made a good point when he wrote, "In my state...." because it may well depend on the state (or country) you're in. From your side bar, under your picture, it doesn't say where you live so no-one from your state(?) can tell you what the rules are there. Maybe you can call the DMV and find out that way.
In my state, it doesn't have to be listed as an RV unless you add a flushing toilet with a black water storage tank.
It's sort of like how much your trailer can weigh before it has to have brakes. In my state, it's 1.500 lbs. In some states, it's 3,000 lbs. but in New York, it's 1,000 lbs. Also, if I remember correctly, in Canada, you have to be able to stop within 27 feet when going 25 mph? Again, your best bet is to check with your DMV in your state and your country. ...Don't know what any of the rules are for places like Australia. Best Wishes!