First the scary part. Someone STILL OWNS THAT CAR. They may have no interest in it currently, but as far as the State is concerned, they are the legal owner. Problem is, you may go to a bunch of trouble fixing up that car (and lots of money) and one day the legal owner can show up at your door with a Sheriff and a tow truck and leave with "your" car. It has happened, not often, but it has happened.
Now, in the case of some clapped out 29 Ford we find in a field, the chances of the legal owner being around is very slim. But a more recent car like the Gazelle might have been caught up in some bad selling deal, and someone is looking for it. One day you are driving down the road and he sees it and there goes your car.
What I would suggest is take the vin numbers to the State motor department and check out what they can tell you. Someone has that title, or at least they can tell you how to legally register it. We all take some chances when fixing up these old "abandoned" cars, but if you can at least try to get a good title it shows you wanted to do it legally.
Don