Odd question here but would it be legal if someone has a normal, production vehicle but decides to put the pre-production camouflage on it because it looks cool?

I mean, its not like its illegal

Like a private owner? Yeah...no.

Not a lot, but every once in a while. They're not always full camo, sometimes just debadged or completely undisguised. Here are all the ones I can remember seeing:

. A bunch of full-camo Tesla Model S's around Stanford in early 2012 (no pics)
. No-camo Audi Q3 in San Francisco, March or April 2013 (no pics)
. Two debadged Infiniti Q50's on the Bay Bridge, April 2013 (pics somewhere in this thread)
. My friend saw two debadged Mercedes CLA's sometime in 2013 (he has pics somewhere)
. No-camo Audi A3 convertible on the Golden Gate Bridge, late 2013 (have pics, but not with me)
. Another friend saw 3 NSX's (the same ones that were at car week) at like 5 in the morning in SF, August 2015

For some reason, I don't recall seeing anything after 2013, besides the Acadia. I'll probably think of some more eventually.

I'll also see some cars just when they come out. When I was back for Thanksgiving and winter break I saw a bunch of new Volts and Civics.

I bet because of the hills they have it is a good city for testing. I saw a video with pre production Cadillac ATS coupes passing Lombard street. In Colorado they have a lot for high altitude testing. In Charlotte I've only seen one. The current C Class about 5 months before the reveal.

Oh, I just remembered that in November 2014 there were TWELVE AMG GT's roaming around the bay area. And I didn't see ANY. Someone posted a picture of about 9 of them at a hotel; I went there the next day and they were all gone :(

I think they were there because they were testing at both Sonoma Raceway and Laguna Seca.

I didn't add this one because barely anybody saw it, but here's another Mercedes that was seen in San Francisco: hee hee

How good is Charlotte for spotting in general? I'll have a connection there when I go back for spring break (although I probably won't be able to leave the airport).

Charlotte spotting I would consider very similar to Atlanta (just a little less, due to size). You'll spot mostly Maseratis and Bentleys but not uncommon for like a few super cars. Go to South Charlotte near the mall, Cornelius and anywhere downtown you'll run into things, looking for them or not. My page is a good representation of what you'll see because I post mostly everything I saw.

have u ever been to Atlanta in October on a Saturday? I saw 10 Ferraris in 6 hours

Atlanta on a sunny day especially a weekend is amazing for spotting. I spotted for a full week in Atlanta for my birthday on spring break a few years ago and every day I spotted at least 30 things, 10 being signifigant.

So my brother saw A Hongqi H7 out testing in Ann Arbor, anyone have any idea why it would be in the U.S.?

According to Autocar, the car is based off of the Toyota Crown platform, which is also the Lexus GS series. So it's possible that he saw a camouflaged Lexus that looks similar.

Ok, that's possible, I'll post pictures soon

Here it is

Looks like someone may have imported their car in from China

It has Manufacturer plates so I'd think not but maybe