Re: what boat is this ????
I'm guessing there's no title or registration, because they'd be a good place to look. Depending on where you're located, that may or may not be a problem, just be sure that you've got legal ownership before doing any work to or using the boat.
It's usually referred to as a HIN (Hull Id#) and can often be found near the helm (the seat w/ the steering wheel :watermelon

or on the side of 1 of the 2 consoles (the 'boxes' the windshield is sitting on) on a plate that looks something like this:
Or in & around the splashwell (its the 'well' infront of where the motor attaches to the transom) or under it
The most likely location however, is to the left of the eye you've got a rope tied to (under the Yamaha sticker) on the starboard side of the exterior transom:
It's probably just 'stamped' into the fiberglass & you will have to look very closely to find it. It looks similar to this:
You can cross check the 1st 3 letters
here for the manufacturer
If it was manufactured after Nov 1972 (when HIN became mandatory) those are all your best bet. Looks post 1972 to me. If it's ever been titled or registered in a state that requires VIN's instead of HIN's (WV is 1) there should have been a VIN plate issued & permanently adhered to the hull w/ rivets.
An actual VIN plate would look just like the 1 in the left front corner of the dash @ your car:
And it's #'s & letters only 'mean' something to the licensing agency that issued it. In WV, that'd be the DMV.
Look thru the info
here for more info @ the HIN
Welcome to iboats
Looks like a nice boat. Be sure it's water ready & safe after you confirm legal ownership. Let us know if you have any questions.