No, the iPhone 5 takes a different looking picture than third party apps that were made for the iPhone 4S; in other words, the iPhone 4S had a maximum ISO of 800, so third party camera apps were made to take advantage of that. Now with the iPhone 5, the max is 3200 ISO, so third party apps simply need to be updated; Camera+ was updated today (not to be confused with Camera Plus Pro which is a completely different app/company.)
Developers have no control over what ISO is used... unfortunately it's not a simple matter of updating a camera app to support up to ISO 3200.