Looks like a Mariner maybe.
Really can't tell till we see the interior, and see if it has been modified.
Splashwell area looks older than 85 from what we can see in that photo.
HIN hull id number should be on the paperwork, and on the top right corner of the transom, on the outside.
As for value, different value in Hawaii than in Alabama, or Ontario, or Indiana, and much of the value is based on condition.
Here in Wisconsin, $2200 if engine runs and floor is solid.