The US shutdown during WW2 was mostly vehicles and large appliances. If you look at a magazine from that time, there were still plenty of goods for sale. The model company Guillow's kept going right through the war, though they did switch to paper because balsa was considered a strategic material.
As all those race car kits show, what makes a subject interesting has very little to do with how many were made. Tucker's one of those makes that's always generated a lot of interest, and is usually high on modeler's want lists.
The kit does look pretty nice. I would have liked to have seen a full engine, but that is still a very nice underside. As for whether it's legit, we'd certainly find out soon enough.