My father worked for Leica in Australia in the 1950s and oversaw a lot of their service work. It is almost certain that Leitz in the US sent your camera to Germany. They also did not 'restore' your camera. They got blank new old stock black paint parts, added the serial to the top plate and other relevant parts of the camera, and put it back together. The new parts have the same paint on them that the old camera had, including that it is susceptible to wear and artefacts including bubbling and delamination.
Legally Leica have no requirement to support your camera after it is 10 years old, although this varies by country. Like companies, cameras don't have morals.
I had a very valuable Leica lens auctioned by Leica last year. It is the most secure and worthwhile approach. They have the best multi-country reach, so all collectors not under international sanctions (and a lot of those have workarounds) can bid. You lose some money on fees, but they buyer's premium covers most of the costs. Both you and the buyer are fully protected through the transaction. For something like a pristine black paint M2, it is by far the best approach. They have current and former Leica employees who verify the merchandise.
Marty