DSLR Mirror

All, and especially those who have Nikon D80 or maybe D200, I have a
question.

I wanted to remove some piece of dust yesterday which started appearing on
the shots at the same place and suddenly found that the mirror is not
looking 100% clean as I would expected. I was using the bright light and was
looking at the mirror under different angles. The central part of the mirror
is perfectly clean but the other part of the mirror around this central
"sub-frame" is looking a little bit foggy, but still as a mirror anyway. I
also noticed two large circles of a perfectly clean mirror near two corners
and two little bit smaller ones. It was looking like somebody just cleared
the central part of the mirror but left all peripheral parts. Is that ok and
should always be this way? I can garantee that nobody even tried to touch
this mirror, I'm the first and the only one owner of this camera and this
camera is brand new, I bought it 3 months ago from Costco.

I sent my question to Nikon customer support last night because according to
my previous experience with another SLR that I had before the mirror was
perfectly clean and I expected this DSLR mirror should be clean as well. The
support confirmed that the whole mirror should be clean and recommended me
to go to the nearest store where I could fix that. I went to TempeCamera but
these guys explained me that this is the part of the focusing system, etc.
and it should be this way, everything's normal and I have nothing to worry
about. Well, where is the truth? Maybe I'm too suspicious and it's really
normal. I'm pretty sure that most of the people who read this NG know about
this problem because sooner or later everybody has to clean his camera up to
remove the dust. I didn't touch the camera or anything inside, just used a
simple standard blower from the camera kit that I bought separately for that
purpose, it doesn't have any visible dust particles now, but the mirror is
looking strange from my point of view. Could anybody explain me that?

Thanks,
Just D.