tedster - 1:25 am on Feb 10, 2012 (gmt 0)
Panda has wreaked havoc on duplicate content of all kinds. I think you'd be well off to not allow those internal duplicates be indexed - it certainly could help, but you'll only find out if you give it a try.
I sure hope those clients of yours weren't hoping for search traffic. If they were, this wouldn't be a good approach for them to use, at any rate.