Yes, iTunes will do that update for you. I don't really know what you mean by a 2012 iPhone. iTunes will tell you which model you have, in the Summary tab. You'll see the "name" that you have set for the iPhone, as well as the serial number for your iPhone. It will ALSO tell you the exact model of iPhone, likely either an iPhone 4, or an iPhone 4s sold in 2012 (but iTunes doesn't show you a year as part of the model). You will see a button where you can check for updates. If your iPhone is at the highest, or latest version of iOS, then you (and iTunes) can't update the software. BUT, you can certainly Restore your iPhone.... I tried plugging the iPhone into my Mac and iTunes said it is actually a 2012 iPhone still don't have a way to update it.
iPhones are generally identified by models. Is this an iPhone 5, 4S, 4, something else?I tried plugging it into my computer and found out the software isn't updateable, and it id actualy a 2012 iPhone. But... I found a site that you can search for an app and it will fing it for versions iOS 3-4.2.1 its a great page,