Altered Vin. How to figure the original VIn

I do understand what you are saying and I believe you are accurate. I may still investigate with local law enforcement to see what there take is.
When I started this thread I was hoping VIN sequence numbers would be stamped on the core support and other places so I could figure out the original VIN. In this discussion it does not seem possible. I have a lot of sentimental memories of running around in this car. It does have some good stuff still on it even though the engine and trans are long gone. it still has the 8 3/4 rear axle that I installed in 1992. It has kh 4 piston disk brakes in front that I installed in about 1994. It is not pretty at all as I had a few accidents in it and put it back together with junk yard panels and panels from the other dart. It has the drivers door from the other dart. I have the original door to this body ato my parents house. I have some of the GT trim still. Interior is destroyed. back seat is actually still good some how. It does have us indy style mag wheels but tires are all gone. I have another set of sbp rally wheels I can put on to roll it. It has manifolds with dual exhaust still. It has gone through many different exhaust systems through the years. I do love this car.
Just leave it be and drive it. The moment you get the police involved in this will be a disaster. Because they'll confiscate the car until they figure out if they can charge you, chances are they won't but the car would be scrapped.

I personally see no issue as long as your story of buying the car and not stealing it is true. If it is, roll with what you've had for decades now and be done.