You can take out an agreed value policy on a boat. My 1997 Wahoo is on an agreed value policy with Progressive because the hull, motor, trolling motor, and trailer are all wildly different years, so it's tough for their program model to estimate a blue book value.
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"Decency is not news; it is buried in the obituaries --but it is a force stronger than crime" ~ Robert A. Heinlein, 1952
I can't give legal advice yet, but this site may have some of the answers you need:
https://texaslawhelp.org/