No neck stamp is no big deal. Sometimes they fade, sometimes they weren’t stamped at all. Even more common in the ‘70s, but I’ve had a couple ‘66s with no stamp either (which is even less common than late ‘60s). You can also narrow this neck down to ‘68-70 era because it still has the small pearl dot position markers along the top edge of the neck. Fender went to black dots in 1970.