Heres what I have for fender bolts on my Lime Green 70 Mach 1 Dearborn Built 3-10-70 and my Grabber Green 70 Boss 302 Metuchen built 11-11-69 car. I've owned the 70 Mach 1 since 9-73 and the cars is original unrestored.
It has bolts with the N on them but they are in other locations. The Boss was restored from original condition in 1988 and the fenders were never removed until that point. I documented all the original locations upon reassembly.