It should be fixed by now, but just in case, I would call Sig customer service, before or after your purchase and give them the rifle's serial number. They will inform you if it has been upgraded and if not, they will send you the required upgrade/notched guide rod kit. It's an easy fix and no more problems.
BTW, welcome to the forum, maybe you can stop by INTRODUCTIONS
and say a howdy-do, if you like what ya see and find here helpful, you may just want to stick around!