In NY it may depend on if that particular trailer had or should have had a
title. I'm not exactly sure before what year NY did not issue titles. but our 1973 popup has a
title. We bought a pre- title teardrop trailer several years ago that had no paperwork other than a hand written, not notarized, bill of sale. The key issue with DMV was that it had an ID number, and it had been in my possession for more than one year when I went to
license it. A big issue may be if the seller will help you after the sale if more paperwork is needed. Or will it be he has your money and it's no longer his problem. Took me a year to get a seller to sign a document in front of a notary to take care of a title issue. In that case DMV gave me a
registration and then a month later informed me they would not issue a title due to insufficient paperwork. Check with DMV.