First and foremost: could you give us the last four letters and numbers of your serial number, the one you can read in System Profiler? Would be useful to check exactly what is your machine.
Returning to your problem: is yours a third part display? Have you removed all the padding when you took out of the box?
Tell us if it's a third party part, because, if that's the case, and if the display is just working fine, it may just mean that the display has a more opaque reflective layer on its back, being meant for use on other machine (for example, when I searched for a new LCD for mine, I was made aware that also some ACER with 13'' display use the same LG, just with no mounts for the iSight, that here has to be taped and affixed to the LCD mount itself).
So, I would check if there's adhesive on the back of your display. If there isn't, I wouldn't bother, I'd buy an iColour adhesive for the Apple, using a red or blue hue to "enhance" the faint light it may go through or the ambiental light and call it even.
Only if you believe it's a cause for giving back the monitor, you may check one meant as an Apple part, with the proper "see through" reflective layer.