When lid closed slight gap on left side

This is considered normal (within spec). Some fix this issue by using these:

http://www.radtech.us/Products/Wildeepz.aspx

The lid or top is made from a single sheet of aluminium, it's tightly clipped to the plastic and aluminium which houses the TFT display. If your gentle, you could flex the lid a little, so it's straightens. Don't flex it too much cause you could end up cracking the TFT completely.

This defect happens if you try to life the lid open from either side of the screen. To avoid it from happening, always try to open the lid from the centre, where the sleep light is.

I had the same issue with my brand new SR MBP.
I was able to fix it by sticking an extra LRF (little rubber feet) from a Lacie D2 hard drive on each corner of the bezel. I then used an exacto to carefully slice down the height of the LRF's until the display closed nice and tight.

The LRF's are mostly clear, so it actually doesn't even look that bad -- almost looks like it's really supposed to be there.

All in all it was about a 5 minute fix. I had noticed the issue within seconds of taking the machine out of the box, and it REALLY angered me -- but now i don't even give it a second thought.

I put some photos of it up here:
http://www.pixeliciouspictures.com/discussion/posts/lrf_support.jpg

D/FW - I also have a new MBP (a 15" one) and this also has a bigger gap on both corners, only a tiny gap, maybe ≤1mm, but on both sides.

it's not a problem (well not to me)

I've seen reports of this out of the box, brand new. So it appears that it's not solely from opening it from either side.

Concave anything will deform with easy, could simply be caused from a change of environmental climate, since metals do and will expand and contract with a rise and fall in temperatures.

wedging a piece of paper under the part that sticks up and the middle, then placing a mediocre weighted book on top for a day or two could fix it. I did this, and it went just fine.

Whatever the reason, there's enough demand to warrant someone to stock and sell corrective "dots" 😉