Well, it sounds like Deputy Sheriff Walthers was as big an expert on bullet strikes on concrete as any who looked at the curb. Although not, so far as I know, an expert on tire rim strikes on curbs.
But he didn’t mention any missing chips from the curb. Just as the photographs do not show any missing chip, or any large enough to be visible, Deputy Sheriff Walters did not observe this either. So the best witness saw no chip missing from the curb. Only a mark.
His opinion seems to have been based on the freshness of the mark. He knows from experience that they become noticeably grayer and grayer after two or three days.
Well, we know that thousands of cars drove by that curb every day. Most of them did not strike a curb, but most bullets, would not strike a curb either. And there were not thousands of bullets fired.
None of this is strong evidence that the tire rim strike hypothesis is wrong and the bullet strike hypothesis is correct.
Seeing the emperor's new clothes yet again I see.
Walthers mentioned that he had seen bullet strikes on curbs before. Also, the mark was deep enough, had enough substance missing, that Walthers assumed it could have been the source of the fragment that stung Tague and cut his face. And, the first photos did in fact show material missing from the mark--it was not just a smudge.
The lone-gunman theory cannot plausible, believably get a bullet or bullet fragment near the Tague curb scar or Tague himself. That's why the WC tried to ignore it for as long as they could.