@pickapaper
Copyright protection does not end when the copyright holder dies -- here is the official definition from the U. S. Copyright Office:
"The length of copyright protection depends on when a work was created. Under the current law, works created on or after January 1, 1978, have a copyright term of life of the author plus seventy years after the author’s death. If the work is a joint work, the term lasts for seventy years after the last surviving author’s death. For works made for hire and anonymous or pseudonymous works, copyright protection is 95 years from publication or 120 years from creation, whichever is shorter. "
Since blueprints are not considered to be "mass-produced" documents, they may also be subject to other protections, as well.
If the house actually still exists, selling blueprints of that house may be considered a violation of privacy of the current owner, as well as possibly endangering the safety of the current owner's family.
I would not offer these blueprints for sale. Alternatively, I would attempt to contact the estate of the former actor to see if they would be interested in owning the blueprints. They may offer to purchase them from you. If they choose not to obtain the blueprints, you may be faced with owning items that will not be salable yet for several decades.
The bottom line -- consult with a good copyright lawyer.
