Hi Nathan,
I tend to agree with Patrick, but if you aren't seeing any issues with SERP rankings then you may not wish to go changing anything.
If you plan to go ahead, here are my thoughts.
Don't go blocking the pages rather look into canonical tags, I asked a similar question yesterday and was pointed to some articles that proved useful.
Moz's guide on Canonicalization would be my first go to.
Plus there is always the Google guide on duplicate content which I would imagine you have already looked at - But just in case that's here.
If it's a case of TL;DR - There is little damage that can be done with correctly set up canonical tags, so get in touch with your web developer or hit the research harder and just set them up wither way. Adding the Canonical tags will do no harm and help rule out any duplicate content concerns.
Hope that helps,
Richard