Where are they??

[Sebastian Nordstrom]

It might be refinished, I don't know. I agree that it is not the most charming brown.
If the top has been switched it would probably have been done a long time ago. I'm no expert but personally I think it is the original top. Is it a common thing to do, make a new top?
It's hard to capture with my not so good phone/bad photographic talent but it does look quite old when you get close, and look at the wear, texture (? maybe wrong word) and grain. The arching is very high. F-holes are nice I think, to bad I don't have a proper picture of the front.

About the rosette - I have only seen this on the internet, on super old italian basses. Maybe the "Johan" something "Nuener" who supposedly made this bass got inspired and decided to ad this feature?