Yep - that is what I did. Got a credit for the mag that I did not get.Not to complicate things, but you can also get one emag and an open hole. This allows you to install 2 emags.
Carl, do you have the EI commander or any other monitors on your dual systems?
The OP has an angle valve engine. Dual Pmags on an angle valve requires some "manipulation" to make it work correctly.