iPhone 4s navigation bar color question

[Sneakerialistic]

My girlfriend and I both have an iPhone 4s and the carrier for both is Verizon. I noticed the other day that her navigation bar is black with a glare affect. My phone has that dull blue color. I like the black a lot better and was wondering if there was a way to change it. I couldn't figure out how to so my question is why we have the same phone running the same version but our nav bars are different?

 

[Semel]

Is any one of you jailbroken? If you have Winterboard installed,you can change it there.