Didn"t older boats have deeper v's and more wood, making them heavier. My
guess
is that a 1990 boat weights more, perhaps much more than a current model boat

I'm not sure that fiberglass weighs less than wood. You might want to rethink
your guess. Hulls are often cored with light weight woods to reduce the weight
below what the boat would weigh if solid rove and resin.

As for the deep V issue, a difference in several degrees in the angle between
the
keel and the chine won't add or subtract a vast quantity of material from the
hull. We're dealing with a hollow, not solid shape.

But yeah, there's no reason to conclude the weight will be *exactly* the same.
Maybe within 10-15% either way, though.