antique cars property release

You may not need a property release from Ford for an old Model-T but the current car owner will need to sign one, especially if the old vehicle has been restored or customized (most have been).  To protect yourself from possible litigation "test cases," it's best to obtain a signed property release whenever possible.  When in doubt, consult an attorney who is experienced in IP law. 

LEGAL BACKGROUND:

In the US, Design Patents are protected for 15 years. Patents that were filed pre-2015 were protected for 14 years.  Utility Patents are protected for 20 years if the patent- holder pays the annual maintenance fees.  After a patent reaches its expiration date, it cannot be renewed

https://patentrebel.com/how-long-are-patents-good-for-us/

Trademarks last 10 years, after which they can be renewed in 10 year increments.

Copyrights last the life of the author plus 70 years.

Hope that helps.