They don't offer any evidence that this particular camera is the oldest surviving Nikon. Even if it is, how could they know that without searching the entire planet? Articles like this should say "oldest known," rather than making a claim of "oldest" that they can't prove.
Even so, if I were a billionaire, I might bid on it.
If i had the money i'd probably buy it, but for now my aim is to one day get a SP as they are more usable than the early S types.
An SP is on my list when I win some money and judging by the price of them I need to win quite a few dollars.
Some years ago I had the pleasure of using an M3 and SP for several months’ side by side and both had their particular strengths. I liked the SP a little more possibly because it felt so much like a Nikon F which of course is no surprise given the heritage of the F.