It could be true but I wouldn't pay extra
Odds are it is "like" the one used in the movie.
The 1976 boat above is obviously not the one filmed as it does not look like the boat in the film. As noted on the first link from the forum above nothing you see below was used in the movie was aboard a real boat. All the interior shots were constructed so they could fit a film crew inside the set too. The cavernous engine room below the saloon is obviously not a plasuible engine room as that much head room below the saloon would be a very large boat.