As a registered trailer manufacturer you are agreeing that you will self-certify that your trailers will comply with the
Federal Motor Vehicle Safety Standards (FMVSS)
Basically you need; DOT tires, Full Lighting , reflectors, safety chains, and - on large trailers - brakes. On trailers
that have brakes the brake hoses need to be DOT and brake hydraulic fluids (if using hydraulic brakes) need to be DOT as well.
In addition to the label placement noted above, The labeling is required. It has to be on when the trailer leaves your facility.
They will never, ever last though on a trailer due to exposure to weather, sunlight, road debris etc -
so you absolutely STAMP the VIN into the hitch frame (neck) in a prominent location – and preferably in a couple of locations.
The stamping is NOT technically required by law BUT it is the ONLY thing that will ever last.