Schopenhauer to the Rescue

It’s funny that while attempting to answer this question, I thought of the Monkey’s Paw and the part where the old couple wished for the resurrection of their son but realized it really wasn't their son they were resurrecting. How is that? It was their son’s body- the same flesh he died with. What is it that made this lump of flesh different? The flesh was not their son because it is not the blood that makes a person a person; it is their personality and spirit. (if not, the movie Lone Star would be all the more disturbing).
The car that Vern currently has in his garage, or in his driveway, is really his Volvo and not the scrap parts made to look as the car by Grace. The reason is simple: the sentiments are the object in question. The material it’s made from is not the object in question.
If there is anything to be learned from the last two days of journeying through blood sweat and tears into the world of philosophy, it  is the theory of the Will and Representation (courtesy of Arthur Schopenhauer) which can be magically be applied to Vern’s case (Don’t worry, Vern; it’s Schopenhauer to the rescue).
Everything in our world is actually two parts: Will and Representation. In others words it’s our internal world and what our outside world looks like. In Vern’s case, the car’s appearance is the representation (not the materials, the appearance). Materials change obviously. For instance, there is the saying, “you never walk in the same river twice”. The will is the way the car is perceived: a twenty year old possession of Vern’s.
If you rephrase Schopenhauer’s theory, it’s all about sensation and perception. It doesn't necessarily matter whether Vern’s Volvo is not made of the same parts any longer. The feelings still exist. Just as we are still “us” although we are always changing: our cells are always dying and being replaced, and we never even have the same head of hair at any moment in our lifetime. Also, the River Nile is still called the Nile although the water is always flowing and moving on. In an egocentric point of view, it’s our perception of the object that makes the object.
Even if Grace did create an exact replica of the Volvo from the same parts, it’s not Vern’s Volvo since it doesn't have the same sentiments latched on (it's not perceived in the same way). It’s almost as if you would resurrect me ninety years from now but place a separate soul inside of me. It’s not me; it’s just my body that has been resurrected. The emotions and perception are different.
In response to the last question, Vern’s Volvo never changed.

Schopenhauer approves this message.

Not really, he's dead.