Energy7, the information on the panel or panel cover, doesn't directly address the breakers.
For an example go to this Homeline breaker
link, and scroll down to the Circuit Breaker Wire Sizes
, take note of the (2) in the conductors listed for breakers 10 thru 30 amps.
Reel-Break, now for the bad news if you are using SQ D QO breakers (I would contact SQ D for clarification) in the QO series
You will see the AFCI's are only listed for one conductor.
The other manufacturers may list their AFCI's for two conductors, you can contact them for this info, I have always found them willing to help.