If you don't notice it then don't worry about it.. that said, one way to test it is to set your screensaver to "Blank" so that the screen goes black, and make sure all the lights in your room are off. Now look at the screen (specifically the edges and corners). If they are brighter than the rest of the screen then you have backlight bleed.
Keep in mind LOTS of LCDs do this, and you shouldn't consider it "defective" unless it interferes with you daily usage... for example if it washes out movies or games.
I also have a 2005FPW, and have a bit of bleed in two of the corners.. but nothing severe enough for me to return it. I don't even notice it during movies or games unless it's a dark scene and I look specifically for it.