J. D. Tippit's death certificate says the injury occurred at 1:18 PM and death occurred at 1:15 PM! Carry on.

Yes, I noticed that as well. The problem is that the death certificate was filed on November 29, 1963 by Dudley Funeral Home, who, as far as I can tell, did not have first hand knowledge about what happened at the hospital a week earlier.
You can't make this stuff up!