You'll find on this site that with black guns, the less said, the better. A lot of the ones you can get from this site, in the classifieds, tend to be used ones that people somehow either got lucky with, or got when restrictions weren't so stiff. I'll be honest here, while your gun will most likely work for as long as you maintain it, we go nuts for all black guns for a pretty good reason. Wait till you hold your first Classic Army M4, you'll see why we love the full black, full metal goodness.
And I do believe the forums here have field lists for your area, but I beleive you need to be age verified before being able to access them. Becoming age verified requires you to be at least 18 years old, and have a way to meet up with a member of the forum who is an Age Verifier. If your over 18, it's actually a pretty painless process, and well worth it, trust me.