You’re assuming the autograph on the yearbook is authentic. Why?
I'm not assuming anything.
I'm simply pointing out that certain "flaws" supposedly uncovered are not flaws, based on the photographic evidence so far presented. E.g., the inconsistent sevens don't mean diddly.
Physical evidence could turn up a forgery. But I haven't seen it.
But the real point is, the fact that he probably did sign a yearbook in 1977 doesn't mean anything. The fact that a bunch of accusers are suddenly coming out of the woodwork after 36 years, with the full force of the media, the Democrat Party, and the GOP establishment is all but absolute proof that they are all liars.