In my opinion, claiming the rights to a product shape comes down to a decision about what's right and wrong. Therefore, the right thing to do is listen to the original owner or manufacturer to determine if they believe ownership entails the shape. Every single person who is interested in the GT40 shape needs to look at it from a standpoint of what would their position be if they had created the shape. Sure, there will be all kinds of arguments put forth by attorneys as to what their interpretation of the law dictates, but those guys get paid for issuing opinions. I don't and neither do most of you here on the forum. Having spent enough money on legal fees over my career to buy several original 40s, I would say our good friends in the legal field will argue either side of this issue, depending on how much it pays. Therefore, look at this issue from a position of what's right and wrong as if though you were the creator of the original shape, you owned the license and you would have income, or no income, depending on how someone interpreted your ownership.
There's enough activity in the market to see from behavior, not words, that shapes are strategic and proprietary. Chevrolet and Ford appear to tightly control Dynacorn's replicas. Chevrolet is particularly sensitive to the shape of the '67 Corvette and to my knowledge, has not authorized a replica shape. I can understand why. The first car I bought with my own money was a '67 big block that had been ridden hard and put away wet. Fixed it with original GM parts and sold it to pay my next year of college. Ferrari has fought for years to ward off encroachment by fighting anything replica at the lowest possible level. That's where the manufacturer\owner needs to start. I recently made a mistake and was directing people to a replica bell housing for the 40 that wouldn't drag beneath the car. I don't own the replica bell housing model; I was just trying to be helpful and friendly. After realizing that the replica was possibly taking one of our forum member's business away (Bob Wood), I quickly began directing all to him. It's his. It's the difference between right and wrong and it really doesn't matter to me how many years have passed since this type of bell housing was actively marketed and sold.
The attention paid to replicas and cars from a long time ago has given rise to new and far better products. Just look at some of the new cars coming out of small private manufacturers. It's amazing what you can get for a mere fraction of what it would cost us to design and reproduce something on our own. To them, I send my greatest encouragement while at the same time look to see how the decisions between right and wrong are transpiring. Just my two cents-
Happy Thanksgiving!
Steve