spark plugs for 318

I have a 340 in my Dart and I just got a set of Champions from Advantage Auto, they are RN12YC, did I get the wrong plugs? I gapped them but haven't put them in yet so it might not be too late to return them if they are wrong. Let me know.

Thanks

I almost forgot they are:
MADE IN MEXICO
HECHO EN MEJICO
FABRIQUE AU MEXIQUE