I don't dispute that a person can own a plat book, I have one for several MI counties, and

 each one has a copyright symbol in it.  Maybe Robert can clarify it, but I think that means I may

use it for my use, but any reproduction of any part for use by others would not be legal.

If you want to give the books to Goodwill, please do and the new owner would legally use it, but

not on a copy machine to reproduce some part for me or others.   Robert may be able to make the details clearer.