Anyway, back to the original question:
The boat has a registration
number - it should have a title. You should have legal documentation
showing that you have legally purchased this boat from the legal
owner, or track down it's true owner and get them to give you title. In the past, I've had to offer a small remuneration to the previous owner, who suddenly realizes that he is still in possession of the property.
If you don't have that, you may have to apply for a salvage
title. In any case, you should be able to track the boat's make, model, and serial
number through it's registration
. Part of that process will include an investigation for theft reports (I think).
In the worst case, and I don't think it will come this, but SOMEWHERE on that boat is an indication of when it was made, and by whom. It SHOULD be molded into the glasscoat, but might be a sticker or plate which might be illegible or lost
. A part number on one of the hardware
components can also give you clues.
Seriously though, you ought to be able to track this through the registration very easily.