Is it helpful to include a progress indicator when there's only two steps in a process?
No it shouldn't be necessary.
You could think of confirm as just an action that brings you from information into whatever is after that step.
Since I would imagine that confirmation is just the click of a button, you should just bundle the two steps as one step. This way the user will perceive the process to be shorter.
You could go one step further by enforcing at the top of the information step that they are only one step away from completing their task, how simple is that!
This is really more of an opinion, since one camp will say it's unnecessary (you fill out the form and click Save/Confirm/Whatever and it shows you a page saying Confirmed!), and the other camp will say be consistent, even if it seems a little odd.
I'd say go w/ your own judgement.