I don't know if there is any issues, but my friend has a '12, I have a '11, and we were told the plugs shouldn't be interchanged. I use BR9's, his uses GR9's or whatever. Supposedly there is a difference. I wouldn't risk it unless totally stuck and had no other choice.
hmmm...this is funny. The guy I ride with has an '12 assault with a "thing" on it. I liked it so much that I bought one at the S'toon sled show to replace my MBRP with. The cooker is the best thing ever.