[josaka]

There are gaps, but in almost all cases in the US in my experience, non-inventor owners record their interest in pubic records at the USPTO assignment database to perfect title: https://assignment.uspto.gov/patent/index.html#/patent/searc.... If they fail to do this, the previous owner could re-sell the asset to someone else who records and could have superior title. 35 USC 261, para. 4. In practice, gaps arise when patent assets are transferred between entities controlled by the same party, who doesn't need to worry about the prior owner trying to re-sell the same asset they already transferred. But event then, the public records get you pretty close to the owner.