I've seen one of these boats as a kid and I cannot remember the model.
It's about as far from a J/24 as you can get...
I am thinking late 60s early 70s model boat.
Here's a J/24, see the difference? Hint... look at the flush deck, and low topsides, a rounded sloping deck.
Far be it from me to discourage you though... but a "Free Boat" is like a "Free Lunch." There is NO such thing.