Yeah, it is. I did that when I painted my car this summer. The gray part is part of the tail-lights, so you just remove the trunk lid liner, unscrew the light panel, and mask off the lights. Prep and paint it like you would any other body panel.
Here are some pics of it, they are tough to see though.
Wow! That does look, very nice! at the moment I am having a new lower bumper grill for the front painted. I have my fog lights added to my SLS, and am removing the SLS style lower grill that is also cracked.
That looks great! I am having the mirror painted Tuesday (some ass did a hit and run but I snagged one from eBay for $110) so I guess I will take off the lights and have them spray it at the same time. It looks a lot better, really does. I have dark blue too, grey isn't too bad on that color but on red or white I think it looks like hell. I'm so pumped to get it sprayed!