Yup. Currently there are magazine adapters for the Ruger SR9/S9, the Ruger American, and one for Glock. The rifle comes with adapters for SR9 and Glock mags, you have to buy the Ruger American mag adapter separately. This also means that down the road Ruger or a third party could offer magazine adapters for other manufacturers' magazines. I don't own an SR9 or a Glock, but I'm buying the PC Carbine. Current street price is less than $550 right now. I'll get one and buy some Glock mags to run in it until someone makes other mag adapters. I may even tinker on my own and see if I can make one that fits my M&P, Sig, and XDm mags.
Hopefully Tony Kidd makes a trigger kit for the PC Carbine. A drop-in trigger pack like he makes for the 10/22 would be sweet as hell.