Not sure about your state, but in North Carolina, you can either get a bonded title(a little more expensive) if the trailer still has ID # on it, bond covers should someone come up later and claim trailer as theirs...Or the old standby, get a title certificate for a homemade trailer and stamp the new # on the trailer tongue and axles(must remove any trace of old #)then trailer has to be inspected by a member of the NC Highway Patrol or a rep of the NC DMV..as being road worthy, then if all is correct , they issue you a new title on the trailer as home made..Now bare in mind that NC is a title state, they title trailers, boats,vehicles,jetskis,etc...Maybe a call to your state wildlife office(or whoever does boat registrations) or Dept of Motor Vehicles might get you some more detailed answers for your state.