I would call it an uncommon car rather than rare. Rare implies it has some unique or additional value, which it does not. It's a nice car, but not any better than any other 126 chassis, you just won't see many of the same.

If it's been sitting that much, I don't think I'd try to drive it home 500 miles. If it has been used that little for the last several years, there's no telling what works, what doesn't, and what might go wrong. I'd ship it home, then start determining what it needs. And it will definately need some fixing up; it's more than 15 years old. If it had been used on a regular basis, then maybe. But right now neither you nor the owner know if it runs worth a darn.

My $.02,

- JimY