The production company bought three boats for filming, if memory serves.
The "Orca" in Jaws as written by Pete Benchley, is a fictional boat, so there's no telling what is was (or meant to be) made of.
The "codfish coast" turned out fishing vessels in ever possible material, so, that makes it hard to assert what would be a likely material.
For the era, diagonal-laid pine or cypress is as likely as anything else. Superstructure work might have been in teak or mahogany (or even in "Honduras Mahogany")
Fictional vessels have their own problems.