I might still have all 6 of mine, there is the possibility I tossed them a couple weeks so. If I have them pay shipping and they are yours. I'll check tomorrow since I have to drag everything out of my storage closet to check.
Okay, decided to not be lazy and be the only person on the thread to do a Google search
The size we need for the rear bumper is M14x1.25x50mm (1.25 being fine pitch for this size, can use up to at least 60mm which is what I use with my aftermarket recovery points with space to spare inside the frame). If you can't find them locally, my source for those bolts is BoltDepot.com - they do carry those bolts in Grade 10.9 (SAE Grade 8 equivalent) which is nice. These are only the primary six bolts - there are two M12 nuts to use with the hitch. I believe those are also fine pitch. Nissan loves dat fine pitch.