2 or 4 USB ports?

Since i've had my Inspirion 8500 I have noticed other then the 2 USB ports on the back there is another USB port symbol painted on the case and a little plastic cover right underneath it that you would have to open up the case to get at it. I have thought about opening it up to check it out but decided against it since I am unsure if it would void my warranty or not. Then the other day i went in my device manager and found out that there are 4 USB host controllers and 4 USB root hubs. I am wondering if any of you know if i were to open up the case and take that little cover off if there would be to USB ports in working condition that i could use without any modification. Thanks for your help in advanced